I liked Google+ when I used it but it was tough to find people I wanted to add. They were too aggressive in positioning it as an alternative to Facebook, where it was about following the people you know in real life. Any service that requires the network effect to take off needs to have a bootstrapping strategy where it's still useful when the userbase is small. Facebook had this even though it was developed in an environment with much weaker competition by initially being limited to college students.
