Forums
General Bitcoin Discussion
- Bitcoin-Board
- Bitcoin Forum (formerly located at https://bitcoin.org/smf/)
- Bitcoin Forums .net
- Bitcoin subreddit
- Bitcoin Tweet Forum @Bitcoin
- Google groups - bitcoin-discussion
- Bitcoin Trading Forum
Language/Region Specific
- Australian Bitcoin forum
- Italian Bitcoin community forum
- Polish Bitcoin community forum
- Russian Bitcoin community forum
- United Kingdom Bitcoin forum
Other
- MtGox Live Traders Forum
- Bitcoin StackExchange - Q&A site, currently in public beta
- Developer mailing list