That Morton's List seems really interesting, actually, thanks for the link.
I went for only three days as opposed to the entire week because of my conflicting school schedule. However, it wasn't what I would describe as "unyielding" (thank god). I went with two close friends of mine, and we actually spent a majority of the time just at our camp talking. While they will approach you every once in a while, generally people don't talk to you out of the blue if you're just chilling out at your tent. Unless you host a theme camp, obviously.
While I'm an INTP I am not a total hermit, and depending on the situation I do find some social environments to be quite enjoyable. Because so much of Burning Man was art-oriented I didn't have too much trouble or discomfort with random people striking up conversation, which back at home would have caught me off guard.
While I haven't participated in any, I know that in my area we have several groups, most of which are centered in either LA or San Diego, that regularly host "off-season" meetups-- which I think are usually referred to as precompressions or decompressions (depending how close to the actual event they area).
But I can definitely see why a need for an off-season "Burning" Community would arise, especially to long-time goers... there was a distinct atmosphere there that, especially in the specific area I live (cough orange county cough) I had never felt before: pure acceptance. Of who you are, what you wear (whether it's just crazy clothes or nothing at all), how old you are, your body type. It frustrates me how materialistic and judgemental the general populace of my hometown is, and to be thrust in an environment where a morbidly obese man spraypainted silver riding a bicycle naked is rarely given a second glance was... well, refreshing, after you got over the shock of it. And 'coming back into society' took some adjusting for me, and that was only after spending three days there. It really changes your perspective on acceptance and even just relating to another human being, despite any differences in the things they like or are attracted to. Maybe it came from just being raised in this area, but prior to the event I would think, 'Oh, well, they obviously like different things than I do and fit into an unfamiliar social niche so I clearly won't like them.' I tend to try to give humans more of a chance, now. Yes, yes, she piles on make-up and her boobs are most likely fake and she probably starves herself to keep her figure and so maybe her purse cost $500, but who's to say she's not a highly intelligent human being that thinks deep philosophical thoughts and suchlike? Maybe it's not very likely but I can't immediatly come to that conclusion without having met her.
And I know the friends that I went with underwent a similar mindshift. It seems like having a whole community to be able to relate to in that regards would be quite nice, actually.