From the On Message dept.:
Mozilla has launched a prototype messaging Firefox extension that it says could eventually enable users to keep track of all of their electronic communications, including email, RSS, social networks and web discussions.

'Snowl' enables users to prioritise messages by importance and have a search-based interface for message retrieval, according to Mozilla developer Myk Melez.

zdnet.co.uk

Snowl Prototype

Intro to Snowl