Question and answer forum for user support?

Piazza is an online forum for ask and answer questions.

Users ask a question that is then answered by other users and/or identified experts. There is only one space for each answer and answers are edited wiki-style, with versioning – so the forum never becomes long and hard to search through.

Emails are only sent out if a user requests to follow a certain question

Questions can be tagged with key words and are searchable