I've noticed that https://together.jolla.com/ is based on StackExchange websites, but is not in the SE network. It would be great if this site would also be a part of SE or if there would be a Q&A website for Jolla users and also a section for SailfishOS and former MeeGo and Maemo.
If you include Maemo and MeeGo, but in particular Maemo, it has a very active (small but very active) community. I recently had to configure a N900 (8 years after it was released) and everything is still in place.
The Maemo community would greatly benefit from a site based on Stack Exchange. What we use now is a (IMO) very messy thread-based question and answers site.
Finding the right answers to the good questions is DIFFICULT!
So please let's start a stackexchange space for the three things Maemo/MeeGo/SailfishOS.