To sign up with Quora, users log in via their Facebook or ID, making anonymity--and the bad behavior it can engender--more or less impossible. And much like on Twitter, users can follow each others' participation, as well as particular questions or topics.

Questions and answers on Quora are moderated and editable to weed out the poor-quality ones. Users are even given a brief tutorial and quiz on the proper way to pose Quora questions. Each should begin with a capital letter and include proper punctuation, for instance, as well as correct spelling, grammar and formatting.

'High Quality Content'

"We're deeply committed to making Quora a resource full of high quality content," wrote Facebook alum and Quora cofounder Charlie Cheever recently in on the site. "So far, we've found that the quiz has helped make more of the questions that new users post conform to the site guidelines and require less editing from experienced users."

In addition to adding and editing questions and answers, Quora users can categorize questions by adding topics to them and summarize answers on a question page. Answers can be ranked for quality, and duplicate questions and topics are combined to keep content from getting fragmented. Through the site's follow capabilities, meanwhile, a stream of relevant questions and answers is created for each user, with a focus on the trust inherent in personal connections.