One element I find disturbing is that since our work email migrated to Google Apps and because G+ accounts are enabled by default when you happen to be logged in to the browser and visit G+, people I don't know or care about are adding me to their G+ circles. While I ignore these, it does concern me that if I click on the wrong button and add someone, suddenly I have established a relationship with, say, a client that can't be revoked easily.