Is AddThis adding to site urls??

My site kept having directories added to it’s url. They were different each time. I deactivated some of my plugins to see if I could pinpoint the one causing mayhem. I was having no luck, but Page Speed was having issues with AddThis and kept saying my page was being redirected. Meanwhile an update for my theme was released so I updated it then reactivated all of my plugins except for AddThis and the problem has gone away. Does AddThis add to anyone else’s url?

http://wordpress.org/extend/plugins/addthis/