Several answers:
In a group, it depends on the makeup of the group. A small group with a few people I know in it, and a few I don't? I generally work myself in quietly, and just act myself for the most part.
In a larger group of people I don't really know, like joining a new forum, or game, or whotever? I tend to go in loud and act like I own the place, once yeur foot's in the door, yeu can relax afterwards.
Both are very awkward for me though, I deal very well with meeting people but underneath I'm scared to the core. The "fake extrovert" is probably the best way I've seen it described really, I LOOK very outgoing, but I'm really not XD
Now in terms of actual definition of extroversion, as in the thought process of explaining things externally? Yes, totally extroverted... but in terms of social situations, I'm a happy hermit, I like living alone, doing solitary work, avoiding groups, etc. As someone semi recently said to me, I view people as tools and objects; things to get whot I want, be it entertainment or something else I desire. If yeu have no use, no purpose to me, though I won't hold a grudge against yeu or hate yeu or anything, at the same time... I really wouldn't care if yeu fell off the end of the earth and died either. If yeu do not provide direct benefit to me in some form or another, yeu are a nameless face of which I have zero attachment to.
As for gender in general... I've grown very picky about it over the years. From back in like the oooooold days of like starcraft/diablo back when I played online and online gaming was fairly new... and female gamers were pretty rare, I learned very quickly to absolutely hate being given freebies. I generally avoid mentioning reference to my gender if possible most of the time, and try to downplay it at every opportunity. Gender means very little to me... after much study of both males and females, honestly, I think both are retarded, and the whole 'gender wars' thing that goes on is foolish. I'd rather have no part on either side of it XD
The stuff people said about friends pretty much matches for me as well. Make acquaintances incredibly easily... have tons of 'people I know', but very few I really consider 'friends'. I have... maybe 1 I trust implicitly, 2-4 others that are quite close, a few others I consider friends but semi distant, and the rest are like 'I know yeu exist', which's my limit there XD
Also oddly enough... almost all my friends are male, and all the close ones are. I dunno, easier to relate to them usually? Talking about 'girly' stuff like clothing, boys, etc, is pretty boring to me >.> Have the odd female friend but they're not really close, just don't mesh well I guess for a variety of reasons. The whole sense of humour thing is likely the largest culprit. Don't think too many women appreciate my style of humour... ah well whot can yeu do XD
I dunno, in terms of the question asked; the normal 'belief' of whot extroverted means, I'd say that yeah, I'm highly introverted in that way. In terms of the MBTI definition of extroversion, it's quite different from the accepted belief, in that case I'm pretty highly extroverted. All depends on the definition.