I've been playing about with Aardvark for a couple of days now.  I must confess I had never heard of the service until it was very quietly announced that Google had bought them out on the 12th February.  Aardvark "was conceived as the first Social Search engine: a way to find people, not web pages, that have specific information" according to their company details at www.vark.com - basically you can ask Aardvark any question you like, by submitting it through IM, Twitter, their own website, iPhone app and I am sure various other methods and Aardvark will try to find another Aardvark user with specialist knowledge of the subject to answer your question. It's a giant pub quiz, spanning the entire world, fantastic!