Textbooks could be selected on a basis of "likes" on the near future.

"Other tools under development that I have viewed--but cannot yet speak about in detail--will rate content in ways similar to Amazon’s rating system or will use a system like Facebook’s to “like” content. Developers of these products feel that if crowdsourcing is useful in the commercial world, why not in education?"

http://thejournal.com/Articles/2012/05/16/Textbook-adoption-opens-up.aspx?Page=3