NOS = New Old Stock. Meaning stuff that's effectively new because it hasn't been used, but is old because it's... old!
Every time someone posts on a thread, it brings that thread back up to the top of the forum list (well, underneath the stickies that are always at the top), so people sometimes post to "bump" their own thread back up to the top of the list, so that it's seen by more people, especially if it's slipped off the first page. It's bad etiquette to do this to your own thread more than once a day, and usually if a for sale post is followed by a lot of bump posts and nothing else, it's a sign the seller hasn't quite got the message that nobody's interested!
Sorry I don't have a frame bag though...