I think you have misunderstood something. Comet is a general way of pushing back events as they happen and there are different ways of implementing comet, two of these ways are using long poll and using WebSockets...<p>Why you should care about comet? Because it is the future of web applications. Look at Google Wave, Facebook Chat or Google Documents - - they use comet to create realtime web applications. I predict that most web-applications will use this technology as most sites today use Ajax in some form.<p>Also note the point of entry into building a scaleable comet application is getting much lower with such tools like node.js, erlycomet and JBoss Netty.