I'd imagine ability to revert a few days, maybe weeks but not much more than that? Would they see the value in keeping copies of every edit and a every deleted post? Would someone building the website even bother to build that functionality.

Maybe not for reversion, but I could see them keeping the edits, since it doesn't cost them much to do so, and it could be useful for spam identification or legal purposes. For example, if an account posts spam, and then edits their comment to hide it/skirt around moderation, or vice versa.

They would also have the benefit of the edits inflating the size of the data that they're selling, which wouldn't hurt.