UNDERSTANDING PRIVACY
This document explains what degree of privacy you can expect while yousurf on the world-wide web and how you can control what information isgiven out about you. The important point to note is that you arein control—nobody can obtain personal information about you unless youexplicitly allow them to.
There are various ways that a site has of obtaining information aboutyou. When you request a page from a site, a certain amount of informationis automatically disclosed in the page-request that your browser makeson your behalf. Once you've received the page, the site could askyour browser for some additional information. While you are gettingthe page, the site could be tracking you by taking notes about your behaviorand storing those notes in an area of your hard disk (cookies) which itcan read back later. And whenever you fill out and submit a form,the information on that form is sent to the site. Each of these aspectsare described below in detail.
Requesting a Page
When you request a page from a site, a small amount of information aboutyou is given to that site. In particular, the site is told the threeitems listed below. Beyond that, the site is unable to obtain anyother information about you with out your knowledge—it does not knowyour e-mail address and certainly does not know your name.
1. Operating Environment
The site is told something about your operating environment such asthe type of browser you are using and perhaps the operating system on whichyou are running. This helps the site present the page that you arerequesting in a way that will best display on your screen. As anexample, the site might be told that you are using the English versionof Netscape 6 and are running under the Windows 98 operating system. Such information is not in any way personal so your privacy is not compromisedby having it divulged.
2. Internet Address
The site is told the internet address that you are currently using. This is sometimes referred to as your IP (or Internet Protocol) address. The site needs your IP address so that it knows where to send the pagethat you are requesting. IP addresses are usually registered to internetservice providers and not to individuals; each time you dial up an internetservice provider, you are assigned one of their many IP addresses at randomto use for the duration of your session. So the site you are visitingcan determine, for example, that an AOL member just requested a page butit cannot determine which AOL member.
Your IP address is not your e-mail address—they are two differentthings. Your e-mail address is the address to which your incominge-mail is sent and uniquely identifies you in cyberspace just as your socialsecurity number identifies you in the real world. Your IP address,on the other hand, is a temporary address that you are using forthe duration of a session in order to get the pages you are requesting. It is no more a part of your identity than is the phone number of a paytelephone which you happen to be using when making a phone call.
But if you are concerned and want to block your IP address from beinggiven out, see the section on Hiding Your Internet Address.
3. Referrer
The site is also told where you just came from. In other words,it knows which page you were reading when you clicked on the link to thepage you are now requesting. This allows the site to know which othersite referred you to it. Also, as you traverse the site, it allowsthe site to know where in the site you were most recently.
After the Page is Received
After you receive a page from a site, that page is displayed. The page might contain programs, referred to as JavaScriptcode, which will then execute on your machine. JavaScript code has the abilityto request some information about your machine and to send such informationback to the site.
If you do not want any additional information given out, you can easilyprevent it. Whether or not your browser allows JavaScript code toexecute is controlled by your preference settings. That preferenceis initially set to allow JavaScript to execute. By changing thatpreference, you will be preventing the site from requesting and transmittingthis information.
The information that the site can request by using JavaScript code inthis manner is usually not very interesting. It includes such thingsas the number (but not the names) of the sites you previously visited,whether or not your browser can execute programs written in a languagecalled java, the number and type of plugins you have installedin your browser, the height and width of the browser window, etc..
JavaScript code is normally incapable of obtaining any information aboutyou that would seriously compromise your privacy. However, with yourpermission, JavaScript code can obtain much more personal information. In fact, it could even read information from arbitrary files on your harddisk and transfer that information back to the site. But you haveto grant your permission before any of this can happen. You'll knowwhen the site is attempting to use JavaScript in this manner because abox will appear asking you to grant your permission. You should notgrant it unless you have absolute trust in that site. If you refuse,the JavaScript code is rendered harmless.
Downloading a File
When you are requesting a file (as opposed to a viewable page), youre-mail address might be divulged as a courtesy to the site. You knowwhen you are requesting a file because its address starts with "ftp://"instead of the more usual "http://".
One of your preference settings determines if your e-mail address shouldbe sent as your password when you request files. This preferenceis initially set to not send your e-mail address so, unless you've changedit, your e-mail address will not be divulged.
Being Tracked by Cookies
Since the site does not know who you are, it cannot possibly be collectingany information on you and has no knowledge of any previous times thatyou visited the site. It does not even know what you've done whileon the site other than knowing where on the site you just came from.
However there are times when it would be to your advantage to allowa site to know something about your previous visits to the site. For example, if you were previously reading a long document and got asfar as page 17, it would be nice if the site could take you immediatelyto page 17 on your next visit.
The only way a site has of remembering information that it can associatewith you is to store the information onto your hard disk and to read itback each time you interact with the site. Such pieces of informationare called cookies for lack of a better name. Of course thesite cannot store a cookie directly but instead asks your browser to dothat on its behalf. And your browser will not store a cookiewithout your permission (see the section on Controlling Your Cookies). Once a site has stored a cookie, it can read that cookie in the futurewithout having to get permission from you. But the site can readonly the cookies that it has stored—it cannot read the cookies that othersites have stored.
Don't be alarmed—a site cannot write to arbitrary places on yourdisk. The cookies that it stores go into one specific file, calledyour cookie file. And the site can't even write there unless yougive it permission to do so. Similarly, the site can't read arbitraryinformation from your disk either.
If a site can store a cookie, it can keep track of all the things thatyou've done by simply writing these things into a cookie which it keepsupdating. By this means it can build up a profile on you. Thismay be a good thing or a bad thing depending on what the site intends todo with the information. For example, it would be a good thing ifa book-seller knew that you frequently looked for information on dogs sothat it could tell you if a new dog book became available since your lastvisit. It would be a bad thing if it then sold that information tothe local dog pound so they could cross-check for potential dog ownerswho do not have valid dog licenses.
Encountering Foreign Cookies
When a site stores a cookie, it is the only site that is able to readthat cookie in the future. That permits a site to build up a profileon your behavior while you are at that site but not on your behavior ingeneral while surfing the web. So at least you have some assurancethat the data that is collected on you (with your permission of course)is site specific and nobody can build up a universal database on you.
But suppose that while you are visiting site sheep.com, a cookie getsstored not by sheep.com but by some marketing site called wolf.com. And sheep.com can cause that to happen very simply by having an image fromwolf.com displayed on its home page. So when you visit sheep.com,you are really making a side trip to wolf.com to get the image andwolf.com can store the cookie at that time. Suppose that wolf.comhas enlisted many other sites to also display its cookie-storing image. Now wolf.com will be building up a cookie that contains information aboutyour accumulative behavior at all of these sites. And the more sitesthat wolf.com can entice to display its image, the more encompassing aprofile it can build on you.
Such cookies that are stored by the site other than the one that youthink you are visiting are called foreign cookies. If youare concerned about the privacy implications of foreign cookies butnot concerned about ordinary cookies, you could give permission for sitesto store ordinary cookies only but not store foreign ones.
Controlling Your Cookies
The way you give permission for a site to use (store and/or read) cookiesis by your preference settings. Your preference could be that yourbrowser should allow sites to use all (foreign as well as non-foreign)cookies, allow sites to use non-foreign cookies only, or not allow sitesto use cookies. Furthermore, in your preference settings you couldstate that you want to be warned before your browser will store any cookie. When you first install your browser, your preferences are set toallow all sites to use all cookies with no warning given when a cookieis being stored; you will need to explicitly change your preference settingif that is not what you want.
If you don't consider cookies to be a privacy invasion and don't carewho stores cookies on your machine, you would keep your preference settingsunchanged. On the other hand, if you are paranoid and don't wantto allow any site to store cookies, you would change your preferences tonot allow sites to use cookies. But there might be a middle groundwhereby you want to allow specific sites to store cookies (your brokeragehouse, for example, might require cookies before it can let you examineyour portfolio), prohibit other specific sites (those notorious for engagingin questionable marketing practices), and be asked about all remainingsites.
You can accomplish this middle ground by setting your preferences toallow sites to use cookies but warning you first. In that case, a box will pop up each time a site attempts to store a cookie. Thatbox will identify the site (it might not be the site that you are currentlyvisiting, as in the case of foreign cookies) and ask you if you want toallow the cookie to be stored. It will also ask you if you want toremember your decision on behalf of this site. If you accept thecookie and specify that you want the decision remembered, the browser willautomatically grant all future cookie-storing attempts made by this particularsite without giving any warning. On the other hand, if you rejectthe cookie and ask to have the decision remembered, the browser will automaticallyreject all future cookie-storing attempts from this site.
By using the Cookie Manager, you can bring up a list of cookies that have been stored on your hard disk as well as a list of sites for which you have asked to have the cookie-storing decisions remembered. And you can selectively delete any of the cookies or sites in these lists.
Evading Cookies
It should be mentioned that even if you have disabled cookies, the sitestill has ways of tracking you, at least while you remain at that site.Presented here is one example.
The site could store the information not in a cookie on your machinebut rather in the links that it lets you fetch. Each link that itpresents for you to click on contains the address of the next page to fetch. But the site could customize that link specifically for you so that itcontains a bit of tracking information as well.
To make this clear, suppose that you visit a site called trackme.com. That site presents you with its home page and that page contains a linkto a second page. What you see on your screen is some text describingthe link (for example, "visit our second page"). In addition to thevisible text, the link also contains the address of the second page, suchas trackme.com/secondpage. But suppose the link on thehome page doesn't contain just trackme.com/secondpage but contains somethinglike trackme.com/secondpage?0 instead. The "?0" might be a code sayingthat you haven't visited the second page yet. Suppose you click onthis link and view the second page. Then you click on a link on thesecond page that gets you back to the home page. The home page thatthe site presents to you this time differs from the one it sent you previouslyin that the link back to trackme.com/secondpage now contains trackme.com/secondpage?1. The site is now using the page itself (rather than a cookie) to keep trackof where you've been and what things you've clicked on.
The good news is that this sort of tracking works only as long as youremain at the site and visit its related pages. Once you leave thesite all of this information is lost. If you should then return againlater you will be presented with the "trackme.com/secondpage?0" link allover again. (Of course if you bookmark a page from such a site, whenyou return to that page via the bookmark that tracking information willstill be there.)
Submitting Information on Forms
Of course if you voluntarily chose to divulge information to the site,such as by submitting a form that the site presents to you, you are knowinglyproviding the site with whatever personal information you filled in. The site is then free to store that information in its data base and touse the information in any way it sees fit. For your protection,many sites are now voluntarily establishing privacy policies which dictatewhat they will and will not do with any information you give them. Each site determines its own privacy policy and makes that policy availablefor you to view.
Keep in mind that there is no policing of sites with regards to theirprivacy policies and they can say in it whatever they want. So whenit comes right down to it, the final decision as to whether you want tovoluntarily submit information to a site will depend on how much trustyou have in the site. You might be inclined to believe what is saidin the privacy policy of http://home.netscape.com whereas you mightbe justified in being dubious about any policy offered by http://www.ripoff.com
You will often find yourself entering the same information on the formsof many different sites. For example, all sites that sell you somethingwill probably ask for your name, your shipping address, and your creditcard number. It's tedious to have to type this in every time. Instead you can ask the Form Manager to save the information from a particularform and then prefill that information onto forms that you encounter inthe future. The Form Manager saves the information on your localmachine and not on any website. When the Form Manager prefills aform with the saved information, that information is not sent to the siteuntil you submit the form. Once again you are in control—no informationis released until you say so.
Divulging your Password
If you are like most users, you've registered for services at varioussites. The registration consisted of selecting a user name and password. Each time you return to such a site, you fill out and submit a form containingthe user name and password that you selected for that site. To avoidhaving to remember a different password for each site, especially thoseyou don't visit often, you might have used the same password everywhere. And the same goes for your user name, providing somebody else hadn't alreadytaken it.
So each site that you registered with has a record of two importantpieces of information about you—your user name and password. Andif this is the same user name and password that you always use, an unscrupuloussite administrator at any one of these sites has enough information togo impersonating you by logging in to other sites at which you are registered. You might not be concerned about this because it really doesn't hurt youif somebody logged in as you at some newspaper site and read what was goingon in the world. But you might be concerned if somebody managed toguess which stockbroker you used, and logged in as you and made some stocktransactions.
The way to protect yourself, of course, is to use a different passwordat every site that you register with. But this means you have tokeep track of every password that you've ever used. The PasswordManager in the browser can help you out by remembering the user name and password that you used when you last logged on to a site, and then pre-fillingthat information onto the log-in form the next time you visit that site. You can then either submit the log-in form with these pre-filled values,or change them before submitting if they are not what you want.
The Password Manager also allows you to see which user names you havestored for which sites. And it allows you to selectively delete anyof these items if you wish.
Hiding Your Internet Address
When you request to see a page from a site, your browser needs to tellthe site your internet address (IP address) so the site knows where tosend the page. This is in effect your return address. Yourinternet service provider has many IP addresses assigned to it and it selectsone for you to use each time you start a session Every time you connectto your provider you will be given a new IP address.
Some users have their own fixed IP addresses which they use every timethey connect to the Internet. But these users are in the minorityand if you are one of them you undoubtedly know about it. So if youhave not heard anything to the contrary, you can assume that you get anew IP address for each session.
Even though it's only a temporary address, you might not want that informationto be given to a site you intend to visit. But if your browser doesn'tprovide this information, the site won't know where to deliver the requestedpage. So this is the one piece of information that you can't askyour browser not to reveal.
If you really want to hide your IP address from the site, you need touse some trusted intermediate site. You go to the intermediate siteand tell it the name of the site whose page you want. The intermediatesite requests the page on your behalf, using its own IP address as thereturn address. Then, when it gets the page, it forwards it on toyou. The site that supplied the page never gets to see your IP address.
There are several sites that provide such services. For a list, see