I questioned about a user “Did(http://math.stackexchange.com/users/6179/did)” at meta. He is a downvoter more than 100k. My several comments is removed by administrator. I was downvoted 10 times by him or them at several question. Please be care.His poor answer are http://math.stackexchange.com/questions/74347/construct-a-function-which-is-continuous-in-1-5-but-not-differentiable-at-2/74383#74383, http://math.stackexchange.com/questions/845816/solve-x-sqrtx-sqrtx-sqrtx-dots-4/845861#845861, http://math.stackexchange.com/questions/424911/find-closed-form-for-1-2-2-3-4-4-5-6-6-7-8-8-9-10-10-ldots/424916#424916, so on. http://meta.math.stackexchange.com/questions/18918/how-to-deal-with-users-consistently-posting-low-quality-answers/18921#18921 Low quality posts・・・ are your answers. Advertisements