I have been answering Yahoo questions for about 5 months. Something I feel sad about Yahoo Knowledge is not mainly the deletion rule but the power of fan system. The sadness of that is the blindness of the fans, who only vote for the people instead of for the accuracy of the answers.
Some have hundreds of fans and when it is time for voting, these fans will vote for them regardless of how obviously wrong the answer is. Even when the other answerer has valid references backing up his/her answers such as from the English dictionary or the prestige grammar websites from American Universities, the wrong answers still got picked.
Sometimes, I felt hesitated to answer some particular questions whenever some particular people answered the questions because of their huge fan system. Still, I felt compelled to answer the questions to provide what I believe to be the true answers, armed with facts and references. Nevertheless, if the answers were up for voting, I was always overpowered by the power of their fans.
There are always times that we can be wrong especially that English is not our mother tongue. I have to admit that I am not right all the time. It is imperative to admit your error and learn from your mistake rather than 一意孤行. This will save yourself the embarrassment down the road. Blindly following someone even when he/she is a reputable teacher or highly regarded expert will do you no good in improving your English or any skill you would like to advance. Do yourself a favor by checking up the references instead of believing what the so-called expert says. The best way to improve your English is to always question the answers unless there are proofs of evidence indicating their accuracy.
By the way, I have a knowledge group "English Forum", where I would post some questionable/wrong answers up for discussion with the accurate answers. If you ran into some questionable answers, send them my way and we will get to the bottom of the truth as much as we can.