- http://news.ycombinator.com/item?id=576677
- http://news.ycombinator.com/item?id=199103
Suggestions:
- http://similicio.us/search.php?url=news.ycombinator.com&...
- I was also going to suggest stackoverflow.com, but you got that down
- http://episteme.arstechnica.com/
Usual hacker suggestions (not necessarily communities):
- http://research.google.com/video.html (Google Talks)
- http://www.ted.com/
- http://lwn.net/ (Linux Weekly News)
- etc.