Collaborative question answering

A new service just started by Google, enables users to post a question to an open community and get an answer. The user has to define the prize for the correct answer to the question, then he can review and rate all the received answers to define the winner(s).

I found it a very interesting principle. However, 2 points can be raised from this approach.

1- Is there real “collaboration”in this community?
2- Is it possible to imagine a different kind of retribution besides money (e.g., social ratings)?

Here a blog post on Google Answers