It is frustrating that the only way to fix a typo is by deleting a comment and posting it anew (My brother once told me, nothing someone says before the word "but" really counts), I have seen it abused by trolls who were scolded by other users, editing out their 'troll' comments to make the other users look like the bad users trying to get them banned (I am speaking out of experience as a former moderator/admin on many communities, and I now work as a mod on a game site), so maybe a few limitations are in order.