Their platform is open too, so, following in the footsteps of companies like Facebook, I expect to see developers flocking to the site to build applications targeting their million+ unique user per day audience.
meebo launched a handful of communication apps (including voice and video chat) a few weeks back when they first opened their API.
Of course feedhaus is also jumping on the embedded widget bandwagon, having released our widget for Facebook over a month ago. We're planning a meebo widget launch one week from today and and an Open Social launch in Q1 of 2008.
Update: Michael Arrington just added his take on the meebo games launch over on Tech Crunch.