I just wrote a simple script to turn rss feeds into notmuch-parsable directories.
Script and docs available at: http://github.com/krl/sluk/ I had run into problems with both of the two other solutions for this i know feed2imap: problems with threading consuming 100% cpu somehow (seems like a local problem, only happended from cron), also it started messing up the maildir writing. rss2emai: downside that you need to send mail when you just want to write it in a directory. also had encoding issues with this. I use this to read all my rss, and tag the ones i find interesting with "recommended", thereafter i use http://github.com/albins/notmuch-to-feed ...to generate a feed from this tag, to spam my friends and enemies. Feel free to yell at me if anything breaks. - Kristoffer