The majority of users are askers ... [Only] a small portion of the user population that provides answers or votes .... In practice, a large fraction of best answers are of questionable value .... Most answerers are not domain experts focusing on a particular topic, but rather individuals with diverse interests quite eager to explore questions of different nature.Please see also my October 2007 post, "Revisiting Yahoo Answers", where I look at Yahoo Answers not as a question answering site, but as what it primarily seems to be used for, a discussion forum.
Many questions are meant to trigger discussions, encourage the users to express their opinions, etc. The expected answers are subjective. Thus, in a traditional sense, there is no bad or good (or best) answer to such "questions." Consider, for example, "What do you think of Red Hot Chili Peppers?"
Note, however, that Yahoo! Answers was not designed with discussions in mind, and so it is an imperfect medium for this purpose. Users cannot answer their own questions, thus cannot participate in a discussion. Similarly, a user may only post at most one answer to a question. Yahoo! Answers has no support for threads that would be essential for discussions to diverge.
Much of the interaction on Yahoo! Answers is just noise. People post random thoughts as questions, perhaps requests for instant messaging. With respect to the latter, the medium is once again inappropriate because it does not support real-time interactions.
This evidence and our results point to the following conclusion: A question answering system, such as Yahoo! Answers, needs appropriate mechanisms and strategies that support and improve the question-answering process per se. Ideally, it should facilitate users finding answers to their information needs and experts providing answers.