I have a web hosting plan. I put some custom graphics on my myspace page that were hosted on my web server. Everytime someone visits my page, it makes an http request to my server to pull the background image I put up. I noticed after browsing my server stats that it reveals the IP address of everyone who visited my page because their visit caused the server to have to serve them a graphic. If you know someone's IP address, you will know exactly when they visited, how many times they clicked on your page and all kinds of sh*t. You can plug the IP address into a mapping program and see where the click came from, their ISP, what browser they were using, whether it was Mac or PC. Crazy. But if you don't know the person's IP, it might not help much. But if that person sends you emails regularly, their IP address can be found in the email headers and if that IP matches up with the person that's been visiting your myspace, well there you go. It can be quite interesting. I've seen some friends of my mine visit my page numerous times a day, some of them dudes, making me wonder if they are gay or something.
Yeah, I'm geeking out here.