I hope it's not BT, Virgin Media or Talk Talk.
The above mentioned providers have apparently reached agreement with Phorm to sell your surfing destinations to enable them to target advertising more specifically at you.
http://www.theregister.co.uk/2008/02...a_summer_2007/
The company mentioned Phorm have gone through several name changes in their time - not surprisingly since they apparently have their roots in spyware.