There are a lot of useful HN apps out there and we thought it would be useful to compile a list of them. Right now the list consists mostly of apps from the HNSearch API contest but please let us know of any others you'd like to add.
Not sure if you would consider it an app, but I run the weekly Hacker Newsletter project (http://www.hackernewsletter.com). About to hit the one year mark with almost 3000 subscribers. I don't use the API (yet), but I do use HNSearch to list a couple classics each issue.
Just added it. I'm actually trying to compile a list of all apps, not just the ones that use the API.
Thanks for adding it and I'll make sure to share this page next issue!