My friend is subscribing to ChaCha, and we had a good time testing it out. The first try was to see if it could define "peripheral neuropathy", which happened to be a test question my friend had received earlier that day. ChaCha's def was graduate level, and would have raised some eyebrows on an entry-level college class.
The second question was "what should I write my Scarlet Letter paper on?" The answer came back within 5 minutes, the idea was morality, which is a little banal but definitely solid.
Our third question was "how many party balloons could we fill with a ton of helium?" ChaCha took about thirty minutes to say it was hard to tell. Hmm, looks like the internet can't figure everything out...yet.