Unison-

Unison is a Usenet browser / newsreader only for Mac OS X. Usenet is one of the oldest distributed discussion forums on the internet.

It's filled with lots of interesting content, but it can be incredibly difficult to get started. Unison makes Usenet simple.
Features:
- Instantly understandable user interface
- Friendly group directory
- Per-group options like auto-loading and offline reading
- Threaded message viewing
- View and post messages in HTML or Plain Text
- Auto-magical file grouping and downloading
- Smart Downloading to skip unneeded recovery sets
- Inline image browsing and music listening
- Convenient Search browser to find Usenet content
- UnPAR / UnRAR / Join built in, no external tools needed
- One-click binary uploads