Introversion is orthogonal to Asperger's
I have Asperger's (slash high functioning autism, pick your term) diagnosed about three years ago at the age of 33.
I'm also an extrovert, which makes some of the common generalisations of Asperger's not so closely applicable to me. While I do have a very real need for alone time and a definite draining effect from socialising with strangers, I also have a very strong need to socialise with people close to me, without which I feel like I'm literally losing my grip on reality.
I think the key difference between draining socialisation and regenerating socialisation is, typically for an aspie, more to do with predictability and certainty with regard to social roles and expectations. With strangers I have to be constantly on guard to ensure I don't upset somebody by missing a social cue and worry that my subtle oddness will unnerve them.
With people who I know well, it's easier to read their body language and avoid clumsily stepping on their emotional toes. Critically, I also know that if I do get it wrong, these are people I can trust to know that I didn't mean it as an offence or at least to just ask me to clarify.
The other kind of socialisation I can find much easier, even with strangers, is when there are clear social roles in the conversation. That way I can "play the part" of the role I'm in and interact in a way that sidesteps many of the easy pitfalls. For example, if somebody is asking for advice on a subject where I'm seen as an expert, then the interaction is less about me personally and more about my place in a predetermined almost prescripted routine - much less demand on those complex social subtleties. And when it's a scenario where my role comes with some degree of automatic respect, it can even be an ego massage! Of course, the temptation is ever present to steer conversations into that arena because it's easy, but it's not a good way into a deeper, more personal kind of relationship, so it comes with risks.
I don't know how many others reading this are in a similar category, but perhaps my perspective might be helpful to some :-)
Sam "SammyTheSnake" Penny