As the New York Times reported last week, Google now keeps track of what you’ve been searching for in order to show you more relevant advertising. So if you’ve been asking about various islands in the South Pacific and you search for “Java,” you’ll likely get advertisements for travel offers, not for guides to the programming language by the same name.

Google’s technology for achieving this effect involves leaving cookies on your computer. But the article notes that Google already had access to the previously visited site, even without leaving a cookie. That’s a standard part of the HTTP protocol for web browsers. Click on a link, and the browser dispatches to the web server not just the URL of the page it wants, but the URL of the page that contains the link on which you clicked.

That datum is called the “referer.” (Yes, the word is misspelled that way in the HTTP standard. Oh well.) This is what makes possible some interesting customizations of web pages. For example, if Joe’s Books has a site that links to Blown to Bits, we could greet people who visit our page from Joe’s with a distinctive message such as “Thanks for coming over from Joe’s Books!”

Now this is all wonderful and a little disquieting. Such tricks make the experience more personal, and perhaps more informed. But is that what we really want? Do we like knowing we are leaving tracks that others know about? And if not, would we rather have them know about the tracks but not tell us that? 

This entry was posted on Wednesday, July 2nd, 2008 at 8:41 pm and is filed under Privacy. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.