Haha, exactly the sort of question I felt like digging into
I'm very much stimulated by the company of others (if I happen to be alone, my "company" will often be online or a book). It can be weeks between occurences of "real" alone time. I love discussing things with people, love having a conversation spiralling into beautiful heights, building intricate webs and castles with ideas, fueled by passion about the subject at hand.
However, I don't think I
need stimulation to function. I'm perfectly capable of being alone. Friends will sometimes be annoyed with me not calling or generally disappearing off the face of the earth, but I just feel that time is different to me than it might be to them. In the same vein, I'd be hard pressed to tell you what happened last week, what year I met somebody or how long it's been since I last met a person.
My internal world. Well, it's a place I like to keep in good shape, since I spend a lot of my time there. I good chunk is designated to cataloguing and recognising patterns and behaviours in the people and world around me. Data collecting, you might say (with added analytic properties constantly in action). A part of me is always watching and commenting on my actions, as if I were reading a book, such as: "she picked up the apple, taking a bite, while staring blankly into space, thinking about what she'd be writing. A few seconds later, her fingers were eagerly stroking the keyboard while she contemplated how ridiculous an exercise it was to write this sort of thing down".
Obviously, at the same time there'll be a control center deciding on the next action, censoring and allowing and most importantly filtering everything that is to be shown to the outside world.
Small parts will be occupied with problem solving or understanding something new, much in the same way I do when I dream. That's what it feels like, anyway.
A huge part will be distracted, day dreaming, thinking about all sorts of scenarios, writing stories in my head and letting me feel alive. That's the important part, but also the part that makes people find me a bit distracted when they walk in on me.
Time alone - overrated. I'm like a camel storing water in that respect. I know I had a year with 14 days all in all spent alone. I've been through times where I was scared to be alone, to face myself, face my thoughts before I learned how to control them. I can easily be in others' company, because I can separate myself into different parts, one alone, one attentive. It's sort of like the way you can read a book and hear every word spoken out loud in your head, although you're reading three times faster than people can talk. There's a discrepancy between realtime and internal time and that time can be used to operate on several levels at once.
I think most of my post just dealt with what people wouldn't realise about an extrovert