Google+ Referrals Drop Sharply: Facebook, StumbleUpon, YouTube Lead the Way

There are many ways to gauge the strength of a social network: users, page views, monthly active users and time spent per page are all effective.  One that I like to look at is referrals, which look at how often a social network is sourcing a link to great content.  For instance, if a blog post goes viral and gets 100,000 views overnight, it’s interesting to look at the breakdown and see where all the viewers came from.