+1 El Topo - I'm still wrestling with how that's supposed to work and whether G+ will fall into a natural use pattern that supports it. Essentially, I think what has to happen is posters have to figure out who their primary public audience is and to share to the appropriate circles based on that. I'm guessing that especially with G+'s current user-base, a lot of folks use Twitter/social networking for more news-gathering activities than social concerns, so there's more of a "shut up and talk work" focus. IE - What's actually going on with some project, not what the CEO had for dinner.
What a news-gatherer would hope is that the founder would post about dinner privately to his Friends circle, and post things about Project to his public stream that the news gatherer is following. The problem is, CEO may have had a really good dinner and wants to share it everyone.
It'd almost be nice to have reverse-circle-invitations, where a person can "expose" certain circles and then when someone chooses to follow them, they can pick which streams to listen to - the "Project" stream, the "Conference Notes" stream, the "Foodie" stream, etc... Twitter does this on some level with hashtags, but in that case, you choose only the circle and not the followee, which breaks when you get dozens of people posting variants the same news with the same hashtag.