I've read a number of posts in the past about ones being disturbed as to whether they can be traced by anyone. It can be worrying to think that our anonimity can be uncovered. For anyone concerned about these things I've found some good tools to prevent you being followed around the internet.
Donottrackme (from abine.com)
Duckduckgo (a search engine that doesn't collect, store or share your data)
These together with Adblocks help a lot.
If you add disconnect.me you can also add Collusion for Chrome (on the Chrome browser) and it will show you all the sites trying to track you.