[jdev] seeking help with presence strategy

[Philipp Hancke]

>> Create a MUC room for every screen and join / leave it as appropriate. Then
>> display the room roster in place of the users roster you currently have.
>> Much easier :-)
>
> Hm, that's clever but I realize I may have misstated the situation a
> bit. The user doesn't merely need to know whether those other contacts
> are looking at the same screen as they are. He/she needs to know
> whether they're online at all

Same pattern, use another online@ MUC for tracking everyone who is 
online. This can be rather noisy if there are many users online but if 
you limit this one to simple join/leave and don't send away updates to 
that room it's ok.