Most or all of the other forums in which I participate allow editing. They have somewhat different parameters, i.e., one will only allow editing within 24 hours of making the post, others allow it over any time frame, all will add a tag line stating the post has been edited and by whom, though one will allow editing without the tag line being added if the edit is done within 2 minutes of making the post.

I like having the ability to edit to correct spelling or grammar, or to add information to the original post instead of having to make another separate post.