[rssident]

You should make an intelligent feed updating algorithm.

If you have at least fifty previous entries from a feed it's easy to predict fairly accurately when that feed will need to be updated again.

That's how the indexer for http://rssident.com works. Saves you tons of cpu cycles.

[sergiosgc]

Most blog providers support pubsubhubbub(the worst protocol name ever). It allows you to avoid polling, by having the content producer notify you of feed updates.

[dpcx]

Except that, even with PSHB, you get polling. I wrote about it here http://www.dp.cx/blog/pubsubhubbub-and-polling.html#.UUcPWLp...

[sergiosgc]

The fact that two feed clients, Superfeedr and Guzzle, implement PuSH wrong in no way leads to the conclusion that, when creating a feed reader, you can avoid polling for every content source that does support PuSH.