As far as I can tell, none. See here: http://www.wired.com/epicenter/2011/06/inside-google-plus-social/ http://www.wired.com/epicenter/2011/06/inside-google-plu

As far as I can tell, none. See here: http://www.wired.com/epicenter/2011/06/inside-google-plus-social/ http://www.wired.com/epicenter/2011/06/inside-google-plus-so... Page 6, specifically: http://www.wired.com/epicenter/2011/06/inside-google-plus-social/6/ http://www.wired.com/epicenter/2011/06/inside-google-plus-so...