Posting on Google+ using the +1 button can be weird. The favicon and the page title shows up ok, but in the description below that, it picks up the beginning of the page's navigation menu. In my case, that's: "Site Navigation[Skip]. Home; About. Mission; Contact; Recent News; Our Privacy Policy;... etc." There's no way to edit this, and this is just gobbledygook of no value to anyone. I'm using the +1 button Google publishes.
After doing more investigation, I discovered that it picks up the page's navigation menu only if you haven't yet entered a Meta Description in Sandvox. If you have, then it gets that, which is the way it should be.