Wundrbar's site says they're a platform and soon hackers will be able to plugin services into the system to be used by anyone. I think we'll see some awesomely clever uses of Wundrbar as its community starts to grow.
That'll be great. One thing I've noticed about yubnub is that I don't have to think about listing the commands because you know most search engines will be in there and the alias easily guessable. Yubnub does basically stop at forming search queries though.