awesome! you can consolidate about 90% of the current push apps in the iPhone store with this one. (in theory at least)

On the fence about this right now... but feed consumers have to do something. I was wrestling with similar issues when spec'ing out a system to collect feeds (yes, millions per hour) for an internal linguistics project... in the current environment HTTP If-Modified-Since just isn't enough.

"A class to wrap Mark Pilgrim's Universal Feed Parser module so that parameters can be used to cache the feed results locally instead of fetching the feed every time it is requested. Uses both etag and modified times for caching. The cache is parameterize

"With the AJAX Feed API, you can download any public Atom or RSS feed using only JavaScript, so you can easily mash up feeds with your content and other APIs like the Google Maps API."

Web service for converting RSS / Atom / RDF / Microformats+GRDDL to HTML / ntriples / RDF / RSS / JSON / Turtle.

"Webpage-to-RSS Pipe generates RSS from any webpage which doesn't have native syndication. It utilizes a data mining service called Feedity ( www.feedity.com ) to dynamically build the RSS, and then only return unique items."

Sam's latest hacking efforts to improve and expand Planet are quite good. Though I forgot to bookmark it a while back, Venus is Sam's less memory hungry version of Planet.

Planet is a lovely bit of Python software that aggregates RSS/ATOM feeds together by date. This is an article that describes how to setup the software.