Welcome to COMET
Do you know what COMET is? According to Alex Russell COMET is the next stage of AJAX:
"New services like Jot Live and Meebo are built with a style of data transmission that is neither traditional nor Ajax. Their brand of low-latency data transfer to the browser is unique, and it is becoming ever-more common. Lacking a better term, I’ve taken to calling this style of event-driven, server-push data streaming “Comet”. "
Basically, is a new approach of open channel between web servers and client browsers, or a push technology: servers can send to the clients unsolicited responses. Other important issue is that is event driven.
This technology needed a name. Now is here, coined to Alex Russell, so I'm almost sure we'll read about it almost everywhere, very soon.
I totally agree with this solution because for a powerful web based application there is a need for two way communication: clients need to request information from servers, but also server should need a way to push information to the client.
Problem is that technology is not there, yet. This would be implemented server-side, in web servers, and is not done yet. Don't search for Apache MODs or IIS extensions because you won't find them, but most important is that is possible with actual technology client-side and some implementation server-side. The sites mentioned above already use it, so it's almost here.
I'm pretty sure this technology will spread rapidly as soon as web servers libraries will be available because allows developers to build interesting and catchy web apps.
I've read Ajaxian comments and mention of old 1997 Push technology, but COMET looks very different: it doesn't start with general ideas but with real implementations, based on today's products (web servers & browsers).
The only problem I see is to provide practical anti-spam solutions. I'm sure many spammers would be interested to push their crap in client browsers. If the user will be still in control and everything would be easy to use (no other installations) this technology could have a bright future, I think. I'd expected for it for some time, because I'm almost sure we'll have it in the future, even if is called COMET or something different.
Welcome to COMET.