Google+ died because it was forced on everyone that had a Google and a Youtube account by psychopathic managers to "grow the numbers". This included forcing a realname policy on non-G+ users that explicitly did not want their online persona connected to their identity. It became the least cool platform on the internet overnight.
Circles were potentially interesting but if memory serves the first implementation was clumsy and I found it limiting because it required you to know what your followers were interested in and, if memory serves, didn't have a way to de-dupe shares so you'd see the same blog post shared by 20 people as separate notifications. My impression of that time was mostly seeing things I wasn't interested in or had seen before.
Forced increased followers + notification of every single one: creepy experience
Cool, I know them.
Oh, yeah, I haven’t talked with her in a while.
Wait, who’s that guy?
Huh, she responded to one Craigslist free stuff listing 3 years ago. Who cares?
That’s the landlord we sublet from for 3 months a decade ago.
… repeat for days …
Make it stop!
Today I have two Youtube accounts despite every effort to not end up with a real name G+ account. And while all of my main activity is on my non-real name account - i.e. the one I actually want, I'm forced to use the other to connect to rewards (Overwatch League tokens to my Battle.net account for watching Overwatch League), because I'm not allowed to do that on my "branded" account. An account I never wanted to exist.
I mean, it was given a team with unlimited free rein. That org's leader did not just want to grow organically.
It picked up where FriendFeed left off when it was acquired by FB. But then was killed by the G+ project.
Facebook already had friend lists with identical functionality when Google+ Circles were created.
In practice, for Circles to actually be useful, they need to be scrupulously maintained.
If you send a message to a certain circle about a pool party, and it turns out that you forgot to add a friend to the circle they will be insulted.
Or if you send a message to a circle that included someone who the message was not intended for, once again, you’re in trouble.
Group chats tend to work much better because they are simpler and are only created when you have a specific need. They can last beyond that need if the people in it end up being a useful grouping for the long term, but this filtering happens organically.