Someone at work asked if Quora is a reliable source of information. I gave an incomplete answer off-the-cuff, and am writing one out here. Perhaps I will email her the link.
It's a simple, democratic concept, relying on collective knowledge and crowd wisdom. People propose questions, however many others as want to answer them, and the rest vote on what is the best answer. You can dig down to see what the 2nd or 10th-place answers are, if you wish. It does not rely on argument or discussion. For what it is, it's great. Best in class.
But it illustrates beautifully how all forms of communication have strengths and weaknesses. The quora community is not a random sample of humanity, or even of online humanity. It is self-selected, and bias effects tend to increase rather than decrease over time in such communities. I suppose it could be partially hijacked, with selected topics being put forward by some nefarious group which acted in concert to vote certain answers up. It would take effort, and the effect would likely narrow.
Here is what I see as biases from my own observation. I welcome other data.
It is a tech-heavy group, with lots of questions and up-votes about computer culture and operation, current science questions about desalinisation or black holes or medicine. Therefore, one can predict the type of answer that will be voted best when the question is some relative of "Is technology really good for us, or is it going to kill us?" The top answer will note that there are risks and unintended effects of all new technology, but holy-moly, look where we've come, technology is gonna save us! It will be a really good answer of that type, thoughtful and well-written, but its overall conclusion is foregone.
It won't necessarily be the best answer, but it will be a good one, and the one this group thinks is best.
It is largely white North American, white northern European, and Northeast Asian in its audience. You will find a lot of Americans asking about China, voting up answers by 1st-generation Chinese-Americans. You won't see many questions or answers by African-Americans, Hispanics, Native Americans, North Africans, or Central Asians. Also, please note, you will not find the Chinese asking many questions about Japan, or Koreans about India. The curiosity doesn't extend there.
There are a lot of young people, with a lot of focus on "How do I get a great job in Silicon Valley?" "What's the best way to make a lot of money fast?" "What is the meaning of life, really?" This group also has the usual outsize fascination with rogues, eccentrics, and Guinness Record-type info: "Who was the smartest person ever?" It's geek trivia night there.
It is generally liberal, especially socially liberal, so if a general question comes up that seems to ask "Is America a good thing in general or are we all screwed up?" the answer which receives the most votes will be of the form "Insofar as we have done and will do liberal stuff, we've been great. But there's too much exploitation, self-congratulation, and other countries do some things better than us." It won't contain any lies, though it may omit some key facts, such as winning the Cold War. It will be the best mid-liberal answer, which is a good thing to read.
OTOH, there is a fair bit of fascination with military topics, and not just cyberwar. There aren't many parenting questions, but there are quite a few about education and training.