The users on Quora are generally more well-informed, articulate and polite than those that use this site. The responses to questions are generally of a higher calibre on Quora as well. There are fewer stupid questions on Quora and fewer trolls because the site is actually administered effectively and people who break the rules are silenced and banned from posting, something that rarely happens here. There is no way to post anonymously on Quora, so people cannot hide the way they do here. The fact that people are generally more knowledgeable and considerate on Quora - askers and respondents alike, is a draw for a lot of people, but the questions and answers tend to be very dry. Another plus is that Quora is a site where people are expected and required to follow rules. And there are consequences for failing to do so. Yahoo! Answers is infested with trolls, they run rampant, many operate multiple accounts, there's very little policing and a fair percentage of longtime users have left.