I'm apparently an extrovert, however, I also suffer from social anxiety and mood will impact my socialization. Like you, if I'm in a down mood, I'm probably more quiet (although if it's close family and few, I tend to want to vent when I'm depressed.) But as far as the anxiety part, I'm worry about looking stupid in front of important people and saying dumb things, so I'm often very quiet...even get mute when people ask me questions because I'm just so overwhelmed with saying the wrong thing (or I've too many thoughts going on in my head to separate). Or, I'll worry about looking boring when not saying anything, but when I don't particularly care for a topic or a crowd. Actually, I've gotten better at accepting this though. If I don't approve of something, I don't mind as much anymore if people see that I don't approve...but I do get bored then sometimes too.

Unfortunately, for an extrovert, I don't get many opportunities to socialize, and then because of that, when the opportunity does arise (ie: have an upcoming social event for my husband's work), I am super anxious because I'm out of practice with socializing...

maintaining contact and/or relationships on the forums though helps a lot.

I'm trying to think moodwise...like when I'm higher.... I mean, I definitely talk more online at that point. Maybe much more! But in real life, well, I don't really have many (or any now?) who will actively listen. I can talk to my Mom, but she doesn't always relate and usually will just say things like "well i hope it gets better" or "i'm sorry". Yeah, like that's helpful. I can talk to my sister too. She knows about emotions and all, but she tends to get very chatty and ultimately just like "hey, what will be, will be. Nothing we can do!" (I don't know. I'm very much paraphrasing and frankly I can't explain well how she reacts, just that it's not always helpful....though sometimes it can be.) Sometimes she'll have good insight, but a lot of times I come out of the conversation feeling like she thinks I'm a looney or something.
My bro, oh I love him. He "gets" me. But he also doesn't really have much solutions...meh! well, maybe the last few times he's said some really helpful things, things that I needed to hear...but he's not around to talk very often.

Most people just want to chit chat and not talk deeply. I'm a deep thinker, deep talker and most people can't handle that...so I'm pretty lonely regardless of mood or opportunity to socialize.