I just answered my own question. Like facebook, once you've posted something you can't delete it, but you can modify it. Good to be aware of that.
You can delete ANYTHING that YOU post on FB as well as anything posted to YOUR status by someone else. I do it all the time. You can't modify a FB post, though, you must delete it and repost.
On eHam, you can both delete YOUR posts and modify YOUR posts. Buttons on the top right of your post window let you do either.