Howdy, HN. I recently finished up a community college course in RoR (I'm usually a learn-on-my-own type person, but being busy I thought that having assignments, etc. would keep me on track with the learning task) and the beginnings of Hacker News Notify was my final project. I had some time this past weekend, so I finished it up and thought some folks here might find it useful.
Hacker News Notify allows you to create a watch list for submissions with particular phrases in the title, submitted from a particular user, or from a particular domain and be notified via email of matches or subscribe to your watch list’s RSS feed. The application scans the "New Links" section of HN (currently) every 15 minutes.
It’s definitely not an example of programming genius and I’m sure many here could whip it up in an hour or less, but hopefully some find it handy in some way.
Thanks.