All the early adopters in my circle of friends tried it for about a month and quit in July. By quit I mean they still have accounts but no longer post content.

I closed my account about 2 weeks ago and in the form that asked me why, I cited the fact that I could not hide my name and keep my full privacy if I chose.

I think in retrospect (as I agree with the consensus that the jury is still out.) the nails in G+'s coffin will have been.

- Not allowing people to keep there name's private.

- 2 not opening to the public before facebook could implement their killer feature (only sharing things with the people I want to ala Circles)

- Lastly in some relation to the first point I think it was a huge mistake to make the 1 percent people (the extroverts who don't mind sharing with the whole world aka your Robert Scoble's and Tim O'Reilly) the cornerstone of the product.

You have to get a critical mass to gain the network effects needed to keep a social network interesting and those people can go along way but the long tail of people will prefer the ability to be more private