Thanks for the tag, @Nancy OShea!
LinSim's answer above is correct, that's why it's marked as such.
To sum this up: all users have the option to report any content to the moderators, then moderators have a few options on what to do to the report if deemed actionable. One of the most received reports is abuse and promotional content, but not all of it is bad enough to ban a user permanently. So we'd edit the post to remove the abusive content, lock the thread if necessary and leave it be.
Because of the ability to edit your own post, a lot of people that had content removed due to abuse/spam would go back and add the abuse again, undoing the edits from the moderator.
This is why this option was recently removed. If you need to add anything to the post, you can reply to it or make a new post and report the old one as duplicate, so a moderator can delete it.
Hope this answers your question.
IMPORTANT UPDATE
We've changed the backend configuration to now allow users that have a certain rank to edit their own posts.
This means new users won't be able to do so until they've participated in the community and reached a particular rank, which will hopefully solve the problem we were having with spammers and abusers. These users are usually brand new and have not posted any previous content.
We will monitor the situation closely to see how this change affects the community as a whole.