Pubsubhubbub best practices

[farski]

I think PuSH is generally still a good, lightweight technology that fits well with podcasting. But I also think some of the most common implementations of it leave a bit to be desired.

I'd like to add some language to the SM spec that clarifies expectations around some parts of PuSH implementation.

Two main points: feeds that do support PuSH notifications should start using the v4 HTTP headers to signify their support, and feeds that don't fully support PuSH should not include hub/topic headers/links.

[farski]

Re: the second point, it's been my experience that Feedburner seems to add hub/topic links to every feed, even if support for PuSH is not enabled in feedburner for a given feed. And if you then try to subscribe to that topic, feedburner will accept the request, even though you'll never get a notification from it.