pubsubhubbub doesn't have privacy/authentication/authorization mechanisms as part of the protocol, so creating near real-time push APIs isn't just as simple as

pubsubhubbub doesn't have privacy/authentication/authorization mechanisms as part of the protocol, so creating near real-time push APIs isn't just as simple as using some pubsubhubbub library. I think its the complexity of coming up with one's own auth system that stops a lot of people from using pubsubhubbub. However, it is pretty awesome for things that are published to everyone.