this blogger lost me when he implied the delicious acquisition was a mistake. that was a brilliant acquisition, and cheap. like in the 20M - 30M range for a very important internet property. it would sell for a lot more than 30M now.
Their business model, as far as I can tell, is to license the presence technology/platform (to other web2.0 sites, mobile carriers/developers, etc), and become the "finger" of web2.0. They want to become a network backbone, after a fashion.
He uses twitter. Lots. Why wouldn't he invest?