One of the best ways to keep track of your friends is using Creepy? I know its not the most original thing, but it works. Creepy is super simple to use. Just enter in a user name (or both) into the text box and let it do the rest. It may take some time if the person you are searching has lots of photos and tweets, though. Once it's done scanning, you will get a nice map of all locations that it has located, and a nice list of locations sorted according to date.
If you want to know if someone is creepy, just find them on Twitter. Twitts are a great way to find out about current events, meet new people, or re-tweet your favorites. And if you are in a tweeter zone, you can search for keywords like creepy, strange, or weird and see what pops up. For example, I am pretty sure that I have seen all of these terms around on MSN recently: twitter, twitter storm, twittering, tweeting, and tweets, etc. But after finding a bunch of weird Twitter tweets in my searches, I realized that it was a very good way to determine if someone was online and creepy.
In addition to the creepiness factor, you will be able to see if a person is using multiple accounts from a single location with the relocation tool. If you are active on all of the social media that allows you to post tweets, such as Facebook, YouTube, and MySpace, you should really take advantage of this. If you are a Facebook fan, for example, you could perform a search for each picture in order to see which one was taken where. And when it comes to Twitter, Twitts offers one more search option called "follower search". With that tool, you will be able to identify who is following you in real time, even if they are located on a different part of the globe! If you are wondering how a person could possibly get location information for you on a tiny microchip in your eye, then using the geolocation tool is one option to consider.