I don't know about a poll, but I always answer questions by anonymous monks. If they do not return, others may learn from the question and replies other than the original poster.

To be even more precise, whether or not I answer a question is completely independent of who made the post. The quality of the question is the most important factor. (the other factors being: a- *can* I answer it and b- has someone else already given a good answer that mine would add nothing new to.)