Why Is My Computer Finding So Many Spy Cookies?

I have the security program called Webroot AntiVirus with Firewall and I usually do a full computer sweep on it pretty much everyday. The reason I sweep it almost eeryday is because there are ALWAYS like 6 or 7 spy cookies on it and one time there was a actual virus on it. Why does my computer find like 7 spy cookies everyday? I dont really have any bad programs for my computer with the exception of Limewire and Handbrake. Are these programs the ones giving me all these cookies? Also I usually only go on Facebook and Fluther. So where am I getting al these cookies from?