People build things on top of HTTP because HTTP is a pretty general, reasonable, easy to implement protocol; most alternative protocols tend to re-invent somet

People build things on top of HTTP because HTTP is a pretty general, reasonable, easy to implement protocol; most alternative protocols tend to re-invent something like it or not become popular. Most protocols resemble or can be implemented on top of (Action, URI, Headers, Body) => (Status, Headers, Body). Most of the improvements suggested to HTTP tend to come in the form of encoding messages more efficiently at the cost of extensibility. Reasonably efficient HTTP servers exist for every platform. I'm not sure exactly what you mean by maintaining state, but if you mean long-lived connections: this already exists in HTTP with chunked-encoding and the new web socket extensions. Stateful protocols tend to be more difficult to write programs for and load balance.