I can pick 300 random real world friends and guarantee that 99% of them never use Google+, even the ones in tech. I have an account and in 1 year I have posted 2 things to an audience of practically no one.

Compared to other social metric's (facebook, twitter, etc), it's empty.

You can't just say that Google+ is not empty when it is so tied to your social structure. I have 3 friends on Google+ and 300 on Facebook. My Google+ is completely empty. Could well be the same for the OP.