"As the Web evolves from its one-way, 'search and retrieve' paradigm
into a medium that's more like an unending conversation, browser
software will have to evolve with it. Flock is showing the way." Arik Hesseldahl - Businessweek
I think I would have to agree. It's built on Firefox too, so all those nice plugins and extensions still work.
Get it here:
www.flock.com