Right when Keith first joined my team I got a request to write a overview article on a AJAX for IEEE Computer Magazine.  Seemed to me like a great opportunity to get his head around the market, the technology, and learn how to explain it at a pretty high level.  Turns out, he did all that, and produced an incredibly eloquent, well-written, and informative article too :).  He got re-print rights, so definitely worth the read:

http://blogs.msdn.com/keiths/archive/2006/05/17/600286.aspx