Not sure about the fact, whether I really understood PubSub but how about the following feature?
I could see as a possible appliation in registering groups of users for PubSub for updates of changed Webpages. Not all websites publish a RSS feed and (at least in my organisation) not that many users are savy enough to handle them at all.
So I would like to “subscribe” them onto a website or give them the tool to do it themselves, so that they get an IM as soon as the content has changed with a link to the file. At the moment this is often being done manually and via Email, which means, that this very notice never gets deleted but stays in the users inbox for ages instead of getting them to check it out and delete the notice…
As a starter using the Admin GUI would be OK but of course some kind of IM robot accessible from the client would be preferable.
Is this something for PubSub at all?