[boyter]

If you are just doing RSS feeds I would say go it yourself. Armed with Feedparser (http://feedparser.org/) you can implement what you want pretty quickly.

For both http://www.searchforphp.com/ and http://www.searchforpython.com/ I wrote my own RSS reader. To make it scale out I just used Pythons multiprocessing to parse it out to 50 or so concurrent downloads. I can tear through thousands or feeds pretty quickly that way. The next step to multiple machines is just throw in a queue system and get a list of feeds from it.

Pretty simple stuff really.