G+, as Wave did, supports more vectors of communication than other tools, and this may be an achilles heel. Regular social media consumers, as much as we bitch about Facebook and Twitter and co, in truth find it convenient to be constrained to certain patterns; simply because the mental and temporal expense of making a communication pattern decision (along with the associated weighing of privacy risks etc) is greater than the perceived (low) value of each microblog entry / sharable communication.

Perhaps I'm just saying "not enough people care enough".