in reply to New PM Feature Request - Node Watch
Sounds similar to this request - maybe the solution there will help?
Update: As per tye's comment in the CB - I'm assuming you are meaning that you want to watch threads and not Nodes. Although I suppose people can update their nodes, too, as I'm doing right here...
Update 2: The problem with the solution there is that you need to monitor what you've linked, it's not automatic. But it's probably as close as you can get without someone actually writing the changes... it's something to tide you over.