Google+ Auto Post to Twitter & Facebook -- Pro Tips Round-Up: Week 3 « Google+ Insider's Guide

This is an interesting way to share your updates to Facebook, identi.ca, and Twitter without having to install an extension. Add +Agent G to your circle, and then log in to your desired account here. You'll receive an authentication string, which you'll need to share with +Agent G in order to authorize syncing. Once you're done, all you have to do when you post updates is share your post with +Agent G.