More instant messaging from ACM Queue

Looks like I am going to have to start following the ACM Queue more closely -- here's a great piece on SIP/IM. Read it and tell me that SIP married with IM is still a good idea.

This other article talks up the benefits of XMPP. Yes, it is written by someone from Jabber, so read it with a grain of salt. Of course, the only remaining opposition is from the SIP/IM folks, and the former article pretty nicely pokes holes in that.

I guess to round out this discussion, something from the SIP/IM camp that picks apart XMPP would be good. Anyone have some pointers?