Ha! Got it! And there's nothing you can do to prevent it!
i now have a record of your IP address, i can use it to find out where you're from. i also (more than likely) have a record of your Operating System and what sort of browser you use too! i also know your preferences in pages to view, and with any hope, what page you were looking at before you came here. Broo-ha-ha! Yes, now that information is mine, what nefarious purposes shall i put it to?
Well, if i'm anything like any major website, probably not a helluva lot.
You see, IP addresses are the pennies of the internet. You can find them pretty much anywhere, and in most cases, it's about as worthless. Sure, i've got an address for you, but it could be one generated from your ISP's DHCP table, it could be the address for your router (and there may be bunches of computers behind that), it could be a proxy for AOL, heck, it could even be some european anonymizer site. Anyone with a few years of network experience or who needs to spend time doing user analysis generally realizes this, well… nearly anyone.
Let's get a few things straight, shall we? Yes, it is pretty darn hard to be completely anonymous on the net. Mostly because if my machine wants to talk to your machine, there's got to be a way for me to get the little bits of information from wherever i am to where-ever you are. It's not a little like calling me via the phone. You've got a number and i've got a number and with a little bit of effort, i can generally figure out your number.
So, why is it that address isn't a precious commodity that needs to be safeguarded against evil? Well, other than the above reasons, let me also mention that big websites (like, say, Google, Yahoo, Amazon, Ebay, etc.) get millions of hits per second. (That's Million and Second) These are spread out over banks and banks of machines stored in various locations around the world. Each record is several hundred characters to several thousand characters long, but at millions of hits per second we're talking about some substantially staggering numbers of records to keep track of. Why is that? Well, mixed in with your query for "Nekkid Britany's Spheres" are tens of thousands of other folks looking for stuff, bots crawling for information (legit and less so), Greasemonkey updaters, personal shopping agents, DoS attacks, Virus based crawlers, Internet worms and, well, damn near everything else you can think of. Trying to do anything with that amount of just plain noise is worthless.
Instead, what big sites do is generally toss the various collected logs into a digital grist mill that culls out just the most pertinant facts, usually several days later. The original logs? Pitched to make way for the terabytes of log information for each of the next several days.
But what about all those nifty personal services? Yeah, see, those work because you've got an account. To the big sites, you having an account is FAR more interesting because now there's a way to track you regardless of what IP/Machine/Browser you happen to be using. Also, since only a fraction of the traffic they get are from folks with actual accounts, it's easier to get and manage that data. That's why sites like Google, Ebay, Amazon and Yahoo! keep wanting you to get an account. Plus if you have an account, they can assign a cookie to you that makes you MUCH easier to "customize content" for.
i'll also note that there's a pretty good sized percentage of those accounts that are "trash" too, but it's far less than the amount of crap a site gets that's purely anonymous. i'll add that smaller sites (like this one) are actually MORE of a threat to your IP based identity because the total amount of information i get is actually pretty darn manageable. i can actually store all of the information into various databases and track folks much more closely than any large site would want to.
See, this is what happens when folks stop being cynical. Cynical people realize that hyperventilating over crap like search engines storing your IP address is f(iretr)ucking stupid. There's far more efficient methods that big sites use to track you that have been perfected long before cheap broadband made static IPs slightly more prevalent in the consumer base, and those tracking methods have the added advantage of working through things like different browsers, proxies, DHTML configurations or any of the other bits of stuff that make IP addresses continue to be worthless.
i wonder if i should note that i've also got his contact info too?