RSS has been the defacto information/news syndication protocol for the web for quite some time now. It is easy. It is simple. But for one little problem, it is perfect for what it is intended.
It is a bandwidth hog for the webmaster who hosts the RSS file due to the polling nature of the protocol. This may not be immediately visible to the reader but every webmaster who monitors his bandwidth usage knows this to be a problem.
If you scan through the backpages of Comp Sc ( both software and hardware ), Polling as a technique to communicate was always the first method chosen due to the trivial nature of its implemenation. But almost always, It has been replaced by a message box / interrupt driven / event dispatch styled architecture.
Even weblogs.com moved away from a hourly crawling implementation to a clean and much faster XML RPC Ping based approach. So why is still that RSS is dependant on polling ?
I pointed this out in a recent discussion on kottke to which Dave replied by pointing towards this post on the RSS site.
I must admit, This was new to me. Seems like RSS 2.0 indeed can be morphed into a publish / subscribe based news system.
I have been thinking along similar lines – the PubSubWeb is where we are heading.