Twitter is a good place for you to search the latest news about Bitcoin, but not good enough for you to discuss it with 140 characters.
So where are the best places to discuss Bitcoin? You can check out the following 2 sites:
There are tons of subreddits about Bitcoin on the Reddit site, and you can also just search "Bitcoin" or any other related keywords.
BitcoinTalk is the largest Bitcoin forum in the world, with a special feature that there are different local sub-forums for Chinese, German, Italian and many other languages.
Besides Bitcoin, both of the above 2 sites are also available for you to discuss Dogecoin, Litecoin, Peercoin and some other altcoins.