Yeah, here it is: the day some of you have waited for, and others have dreaded: I'm finally gearing up to offer my report on Sunstone.
I should explain a little about what Sunstone is, since it has become obvious to me that even people with a background in Mormonism aren't quite clear on that.
Sunstone's website states that it is the "sponsor of open forums on Mormon thought and experience." The forum I attend each summer in Salt Lake is a symposium on Mormonism, not a conference. The two words are interchangeable in many regards, but General Conference in Mormonism means something special: it's a big meeting held every six months (the first Sundays in April and October) during which the faithful listen to exhortations from the brethren and reaffirm their commitment to the church by sustaining said brethren.
There's very little of that going on at Sunstone, which is probably one reason that some years ago (10? 15? anyway, before my time) the brethren issued a statement condemning alternative forums, which was, I am told, understood to be a condemnation of Sunstone in particular. Scholars who worked at church institutions were warned that their jobs and their membership could be imperiled by participation in Sunstone. As a result, attendance at the symposium declined sharply.
So you won't find too many conventionally devout Mormons delivering papers at--or even attending--Sunstone. It's not that you won't find any; they're just not the majority. Instead, Sunstone is a place where people from the fringes meet and mingle. For instance, at the plenary session one evening, the opening prayer was given by Susan D. Skoor, an ordained apostle of the Community of Christ (formerly known as the Reorganized Church of Jesus Christ of Latter-Day Saints, the branch started by those Mormons who did not follow Brigham Young to Utah after Joseph Smith was assassinated in Illinois--that's right, they ordain women now, and Apostle Skoor was extremely cool) and the closing prayer was given by a guy whose name I didn't catch but who freaked me out with his peremptory command that the audience stand while he prayed and who (I later learned) is a member of a fundamentalist polygamist offshoot of the church.
You ain't gonna find too many of those sorts offering prayers in mainstream Mormon functions.
I'd guess the majority of attendees are people who still maintain their activity in the church but are fairly unorthodox. (I admit I don't have data to back this assertion up, and I might be wrong, but it seems a reasonable guess.) The next biggest contingent, I imagine, is people like me: cultural Mormons who don't practice but maintain an interest in the religion that was once so important to them. Also in the mix are scholars who are not and never have been Mormon, but who have an academic interest in it. There is also a respectable showing from members of the Community of Christ (which never embraced polygamy), and from polygamist groups as well (which never stopped).
The only group not represented is any group that has as its raison d'etre convincing people to leave the Mormon church, because although Sunstone is most definitely not devoted to Mormon apologetics, its goal is to explore the role Mormonism plays in people's lives, not end that role. At Sunstone, you can voice long and loud the opinion that the church is entirely full of shit; you just can't make it your work to convince everyone else to feel that way too.
More to come.

Your synopsis was interesting and it sounds like Sunstone is something very much needed and reviled at the same time.
I think you've pretty much nailed the Sunstone demographics. John Remy currently has an interesting post over at SunstoneBlog that discusses and questions Sunstone's boundaries. Works as a nice companion piece to what you've written above. http://sunstoneblog.com/
By the way, I just listened to Susan Skoor in the "Women in the Ministry" panel discussion this morning on my iPod while working out and later driving to work. Did you attend that session? I highly recommend it.
Glad you found the intro informative, Dale. Matt, thanks for recommending John's post--very interesting. I guess a lot of people have the same questions about Sunstone, why it feels so welcoming to some of us and threatening to others.
I didn't hear the "women and ministry" panel--it was the same time as my panel on straight women and gay men. And I forgot to pick up any cd's of the sessions I missed--or even of my own. One more to add to the list.