Used to be a very good and almost essential add-on... However, it seems that the developers turned it into an adware / spyware during March, 2013. Developer's site (ppclick) seems to be a scam or ad-site as well – when it is working. The site has always been an advertiser one according to the archives. It is recommended to stay away from this add-on and the developer's website as well. Beware and do not install, but rather tweak and update some (clean) old version of the add-on for yourself.