Push was an interesting idea that never lived up to its hype. Don't make the mistake, either, of thinking of P2P only in the Napster context. Yes, file sharing is an enormously valuable component of the P2P genre - though the entertainment industry's paranoid reaction could damage the most promising computing architecture in years. But file sharing isn't the only promising use. It may be a miniserver designed to send out limited kinds of data, but it's a server nonetheless.
Servers can be peers.
The domain name system, which lets computers find one another on the Internet, is a group of servers peering effectively with one another. Many volunteer, nonprofit projects are in the works, but several for-profit companies have sprung up to take advantage of this notion, too. The Web has been turned principally into a read-only medium, but it wasn't designed that way. New products allow people to write online from inside Web browsers, saving their work directly on the Web. The real excitement, though, is in what' s yet to come.