SubStream: Yes, what you wrote should work fine. Although instead of storing it as a global var, you could use modulo as well
Really though, set_task was made for this type of stuff.
Oh, and Rix, I don't think that's what he's looking for. He want to track user time, not display that message to everyone every 15 seconds. Furthermore, you have id as a parameter in the textloop function while set_task does not pass along an integer parameter but rather an array parameter and the one you provided does not pass any parameters at all. Hell, it doesn't even loop like the name suggests it would.