Also - those nice Amazon links on the right of the page link to Yedda's affiliate account with Amazon.  So while you get a book that will help you out, Amazon gives some money to Yedda at the same time.

I would imagine down the road Yedda could sell a book based on our contributions.  The TOS says that Yedda owns the content we post.  They could also sell our answers to a publishing company that is producing a seperate book as well.