I regret to say I'm ending my participation in MathOverflow, for the same reason I decided a decade ago never again to edit Wikipedia. It's hard to express how disheartening it is to spend hours of volunteer labor explaining stuff---in this case, in a way that at least 19 MO users apparently found useful---only to have your work overridden by a smaller set of users, for being (part of something larger that's) "off-topic" or whatever it is. Who the hell has time for that? From now on, if I have math questions, I'll post them on my own blog. Was nice being here for 6 years; thanks everyone. — Scott Aaronson 16 hours ago

Ah, maybe I just didn't understand how MO worked. I thought my work was, not deleted (nothing ever is on the Internet :-) ), but permanently deprecated---similar to what happened when my students and I wrote Wikipedia pages about some CS theory topics, which were then promptly deprecated for being "not notable." In this case, though, it seems to have taken less than a day for the "off-topic" verdict to be reversed---I'd say clearly the right decision, since while the question wasn't perfect, it's not hard to error-correct it to something of real research-level mathematical interest. Thanks MO! — Scott Aaronson 37 mins ago