You are right, the original poster can rename their topic, and the notification feature will use whatever the current topic name is.
Can someone “close” a topic? Normally, no.
But the discussion you are referring to is in the classifieds forums. So for me, this is a grey area. Indeed, in that particular thread, I do not believe the “discussion part” of it has been changed – just the first post, which had contact details and the list of items.
How could I blame anyone for wanting to remove their contact details? I am actually surprised whenever people post their personal contact details to the world. I plan to put up a bunch of things for sale, too, because I’m moving house soon, and you better believe I’ll be removing the contact address when the sale is over.
To me, this highlights a weakness in using the discussion forums as a classifieds system. This is why I was so interested in working with TaiwanHo! when they were setting up their classifieds database at taiwanho.com/classifieds
If anyone can recommend a php/MySQL based classified system, or show me how I can pull parts of the ads from the underlying database so I can fashion a printer friendly version, I’m all ears.
Check back in here in the future, we’ll see what we can come up with