Google+ was so weird, for a considerable amount of time it was invite only, you needed some form of connection to get in – turns out this wasn't great as they assumed it would be. I can only assume that is the reason they pulled a massive U-turn and decided to foist it upon anyone and everyone after the fact, which, it would appear, was also a bad idea.
It had some cool features, like how you could group/rank who you were following. It was just missing users
I think the best allegory I saw was someone trying to get into an exclusive club with a really long line. They finally get in and the place is empty so it sucks
I'm wondering if Bluesky is doing the same thing to itself
Google+ was the home of the online TableTop RPG scene out of whatever reason. We used hangouts for videochats back in the day, because you could directly stream them to YT, which was also favoured by the RPG Streamers at the time. It was wild, Google Hangouts frames were hot shit to portray your character stats and stuff. I really miss those times...
If I recall, they've just finished up a round of seed funding. I've heard precious little about the project itself, though. You may be on to something.