See especially the comparison of the photo site, 500x vs. Google+, on the issue of nudity in photos or not. (500x - yes, Google - no)
See also the first paragraph re. the rapid growth of Google+ compared with other social media sites.
http://www.macgroupus.com/e-blast/sekonic/Webinar/Sekonic-Webinar-Part2-08112... The presenter, Joe Brady, does very good webinars. I've seen quite a few he's led. The last one, part 1 on portraiture, had the most viewers this company has ever had for their webinars. :-)