ShoutChat works just fine on any mobile device.
https://www.ubbcentral.com/forums/ubbthreads.php/ubb/shoutchatShoutChat can be reached by clicking on the header of the the ShoutBox island.
For an admin, they can copy that link and integrate it in to other parts of their sites interface if they choose. Then give access to posting messages to it, only to the user groups you choose. If you want only /other/ groups to have access to it, you could wrap it in a custom script that only allows that group to access it.
There are currently no "rooms" or notifications of when a user is offline or online. But the intent of the Shout* feature (IIRC) was to get the entire forum group to on a twitter-style conversation, and discussing forum related topics in real time.
So with that being said, look at the ShoutBox/ShoutIsland feature as your forum's own twitter-style billboard.
...or install Twitter and use their API within an Island -- and make your users create twitter accounts... accounts that wont be tied to your forum's accounts. This could probably also be done with Disqus or Facebook or Google+, but Shout* is already integrated pretty well with your forum's current member base.
I hope this can be helpful to someone
