Hi, I was at work when some of the first AMAs in the current wave of AMAs were posted (yes I was getting paid while reading them)
So it started after someone posted an AMA about being raised Mormon in Utah . This was in response to the memes/discussion about "soaking" and "jumphumping" (weird Mormon sex-without-'having'-sex stuff). It was an interesting AMA, I'd recommend checking it out if you haven't.
After that I believe the next one was an AMA posted by someone raised as a Jehovah's witness. Work was busier at that time so I didn't really get a chance to check it out thoroughly.
I didn't see any more serious ones after that, though there may have been. Then people were posting joke ones about being raised in cults or other unusual environments, which spiralled out into even more unserious AMAs, such as "I was raised by well-adjusted parents" and "I won't answer your questions but instead silently judge you for asking them," or my personal favourite: "i emerged fully formed from a contextless void, ama"
Look out for my upcoming NYT article: The cause of the sudden wave of AMAs? China's new style of information warfare