It does run a Service in the backgound that kind of bogs the computer down, AVG Anti-Spyware Guard-Service. Most people should leave this running, but I like speed so I put it on manual and Start it back up when I want to use the program.

What does it do, it scans your computer for spyware and trojan horses as well as other malicious software. If it is a Cookie, delete it, if it is a folder or Registry Entry, google it to find out what they are before you remove them.

It is a way for Companys like Double Click and Gator, to track where you go on the Internet, what Web Sites you visit, they say, it's put in a general database, so they can determine what is clicked on, like Ads, etc. But who really knows, they will not show anyone what they are doing with our Information and they are doing this without our permission. So we have Anti-Spyware software! Also now on the internet you can just visit a malicious site and get something put on your computer or get tricked into letting them install something. So it is a must now days to have this.