Here are a few online communities and forums related to cryptocurrency:
- BitcoinTalk: A forum focused on Bitcoin and other cryptocurrencies, with sections for technical discussions, mining, and trading.
- Reddit: A large online forum with a dedicated subreddit for discussions about cryptocurrency (/r/cryptocurrency).
- Telegram: A messaging app with a number of groups and channels focused on cryptocurrency.
- Discord: A messaging and voice chat app with a number of servers dedicated to cryptocurrency.
- LinkedIn: A professional networking site with a number of groups dedicated to cryptocurrency.
There are many other online communities and forums dedicated to cryptocurrency, so you may want to do some additional research to find ones that are relevant to your interests.