sQusi is both a free Internet Explorer add-on and a Firefox extension in one package. It is designed to take the clutter out of browsing and to prevent marketers from tagging and tracking you across the web.sQusi combines a continuously updated global database with a local one that you can use to override global settings to block or unblock URLs of your choosing. Now you can say goodbye to the Hosts File editors that choke your machine and to multiple add-ons/extensions. sQusi combines the functionality of several available extensions (ad blocking, script blocking and cookie/cache cleaning) in a single application that requires zero effort on your part. sQusi will work with both Internet Explorer and Firefox on Windows XP and Vista.

Version 2 blocks ads within Windows Messenger Live, Yahoo and BitComet.