NewsBiff is a command line utility that helps keeping track of messages of interest on NNTP newsgroups. It looks for postings matching given criteria and outputs results as plain text or Atom feeds. I originally started writing this to be notified of answers to my own posts.
To avoid multiple notifications, NewsBiff maintains a database of known articles as a newsrc file, similar to those used by popular news readers like Slrn or Gnus. The newsrc parser is implemented as an independant, reusable module.