Shoutbox

Yes - Maybe a ping asking for a responce - if it get one from the other user saying it has got sweetim then don't send and tell the user so, otherwise execute as normal.

And yes, the current phrasing is poor, and makes it look much like many other dodgy services - Something like To see this you need SweetIM - just so people have abit more idea of the purpose of the message.

Edit: And yes, make sure there is nothingthat could be percived as spyware/adware, and more clear terms that highlights the nature and usage of data and the like would be good, rather than so vague - because although this covers you it leaves the rest of us thinking it is some advert stunt.

Also - Active members and well known users help - You could have posted before about the project, and this would have been a good way to research your target market before designing.