RSSCloud is useless, for increasingly ridiculous reasons:
10e2 It's idiotically-designed
(he thinks traditional SOAP posted to a resourcey URL is REST!)
10e4 It doesn't help centralized aggregators scale at all
10e8 It doesn't work with NATed clients
10e16 It was specced/never-implemented/forgotten by Dave Winer 8 years ago
a) I'll take that back about Matt -- he's not an idiot -- he just writes code naively, and accidentally became a prominent BDFL after SixApart repeatedly threw away their own accidental prominence.
b) Dave isn't an idiot -- he's a poisonous egomaniac asshole that successfully weedles his way into anything tangentially related to any of his pet projects, and proceeds to do whatever he can to be credited for other people's work, impede progress, and fuck people over. It's his designs that are idiotic.