The folks on HN seem to be of a generally higher quality than elsewhere on the internet (e.g., Slashdot). Amazingly, spammers, trolls, and opportunists have seemed to largely ignore HN so far (knock on wood). I agree an HN meetup would be broad, but I would hope that it would bring that same higher level of quality.

Can you imagine a Slashdot meetup? Could potentially work at a combination circus-firing range-porn addiction support group, all taking place in your Mom's basement.