If you want multi master in Postgres, I think BDR is going to be your best option, but the version for PG 10+ isn't open source so you'll have to pay for it. We're using the open source version on PG 9.4 currently in production, it's worked fine so far.
I've noticed most people are not sure of what exactly they need to do to comply (me included). With the ambiguity, it seems the best way to cover yourself is to just be able to say you consulted a legal team in the past and did what they told you to comply. This has obvious costs associated with it.
When I was in school, international students had a week prior to orientation with their own orientation. They formed friend groups from this orientation, so it's not too surprising that they would stick to those friend groups rather than then branching out to the people they have less in common with the following weeks.
I'm doing the same thing but with Asana just because it's what I use daily anyway, using their sections as the types. It's not great but like you said, laying it out in the beginning keeps the scope contained and I can list off bugs I find.
I've been working on this game in my free time for a while now, it was time to just hit the button and submit it. So far the feedback has been positive, but the size of the game might be too large, primarily caused by the music within the game. I might push a new version this weekend with less music that is loaded over wifi after app download.
What is the expected use case? Generally people set their social media to private for a reason. Maybe I'm just being negative, but I feel like the most common use case would be to say bad things about someone where they haven't thought to block it yet or don't know about it.
If you're just looking for a hot standby and dont need a multi master setup, you can set those up just with pg. https://www.postgresql.org/docs/9.4/hot-standby.html