We are an established group that has been going since our meetup for the 2018 "Meetups Everywhere" event. If you email me, I can add you to the email thread where we plan future meetings—or feel free to just show up!
We have a pretty healthy crowd of attendees for the size of the area, with about 5-7 folks typically turning up out of a pool of 12 or 13 that has been slowly growing as people find us through these posts and the open thread. Most people are local, but folks come from as far as Connecticut or NH.
There's no "format" or suggested readings. Although it's not rare for us to touch on SSC articles and related topics, the conversation varies wildly, and you are welcome even if you're the most occasional SSC reader.
This meetup is at our default spot of Packard's Bar and Restaurant in Northampton, in the "library room" (go all the way to the back and take a right).
Hope to see you there!