If you wanted to go crazy you could extend it so that one could edit emails to apply inline (if there's an email in the job add) so that one could apply to many jobs at once.
I must be being blind but there doesn't seem to be a search bar. How I use the existing hn threads is to search through using Find for some criteria like "UK".
This is the first thing I've ever made for people to use. I'm pretty nervous about showing people. I made it because I wanted to try out Firebase.
Future features: Better UI/UX, more login options, keyboard navigation, search bar.