After just more than an year of the term AJAX being coined, now comes Comet – increasingly being called "the new Ajax". And as it was the case with Ajax, its just the terminology thats new, not the technology. Another detailed article on the same before it was called Comet.
Unlike Ajax applications, "Comet applications can deliver data to the client at any time, not only in response to user input. The data is delivered over a single, previously-opened connection. This approach reduces the latency for data delivery significantly."
Its set to appear in more and more applications as it promises "to improve application responsiveness for collaborative, multi-user applications and without the performance headaches associated with intermittent polling"
But will it create as much buzz as Ajax did in the last year? Seems unlikely. Because its a delta over Ajax in terms of performance improvement but not a huge change in the user experience which was the primary reason for the hype around Ajax.