That's why it's in beta format, right? Apparently, the sharing/contact issue that plagued Google Buzz is also apart of the Google Plus experience, at least according to reports. We can't rely verify whether or not the issue exists or was corrected due to the invitation-only status Google Plus maintains.
The privacy issue with Google Plus was discovered by Tim Bradshaw with FT Tech Hub, and while he says it's not as severe as the Google Buzz issue that resulted in Google shutting the function off altogether, the resharing option stains Google's approach of making their social platform one that respects privacy. The issue has to do with the resharing feature, which, once selected, shares with everyone in your Google Plus circle. That's fine if it's something you want to share, but what if it's something the original sharer wanted to remain between the people they shared it with? Bradshaw has more:
Say a close friend of mine posts a picture of her kids to her "friends" Circle. With the "share" option on every Google+ post, I can reshare this with absolutely anyone, from another Circle to which my friend does not belong, right through to making it completely public. The same loophole applies not just to photos but to any kind of post, as far as I can tell.
If she'd known about this risk (and how would she?), my friend could have disabled resharing using the drop-down menu on the right-hand side of every post, but it doesn't seem to be possible to do this before she'd already published it. Google+ also, for now, lacks any way to turn off resharing of all your posts from within its privacy settings.
As for the last point, it's reasonable to think that's something Google could address quite easily, so if there's any kind of outcry, they probably will. Furthermore, if someone wants something to remain private, or between friends only, why share it in what essentially becomes a public forum. Direct messages -- or whatever Google calls Plus' private mail service between members -- work much better if you're wanting to keep something relatively quiet.
Sharing across networks is one of the appealing natures of social media platforms, or at least it is until someone actually sees the power of these networks and finds their content in places they'd never imagine. One could even argue the entire concept of social Internet use goes against the concept of privacy, so temper your expectations accordingly, but then again, warnings never seem to work out very well. People want reactive measures more than they preventive ones.
According to Bradshaw's report, Google has been informed of the loophole his post discusses and has responded, saying that's what the invitation-only period is for, finding and correcting bugs like this one. Bradshaw finishes his report by discussing the fine line between privacy and sharing, while saying Google needs to balance the two. This is where he and I disagree for the simple fact that "user beware" and "personal responsibility" come into play.
Is it Google's job to teach members how to use Plus' privacy settings or is the member, one who likely joined quite willingly, have a level of responsibility in knowing what will and won't happen when they hit the share button?