Sounds like G+

In my experience, Google+ is a great place to find passionate communities of small niches. Tabletop role-playing games, for example, have thoroughly adopted G+.

Google+ falls down for mainstream users, though, which is where the "no one here" perception comes from.

If memory serves, Google Wave was the same way: great for the people who used it, but the value wasn't perceived by the majority.

It's also great if you treat it like an intelligent twitter and follow science and tech people. Also party mode on events is killer.

It was Googles first attempt to create their own social network. In the end, it crashed and burned just as hard as Google Buzz did.

Wave was not an attempt to create a social network, it was an attempt to create a next-gen replacement for Email.