Twitter is a different situation. I know very few of my followers and therefore find it easy to tweet very personal information. It's a good outlet in that respect. Mostly I tweet quotes – but they are quotes that are relevant to how I'm currently feeling. The other day I made a very personal tweet and to my surprise got a very personal response – from a stranger. It helped. Also there is a large following of people interested in mental illness and I find it comforting knowing they're there. It's helpful reading their tweets.
The blend of comradeship and anonymity between Facebook and Twitter can assist in managing the loneliness associated with bipolar disorder. Knowing there are others to reach out to is helpful. Social media has become part of my day, and part of my personal support system.