The Wall Street Journal reports on the expansion of “The National People Meter” to the Twitterverse:

Earlier this month, Nielsen published its 2012 Social Media Report, finding that “consumers continue to spend more time on social networks than on any other category of sites—roughly 20 percent of their total time online via personal computer (PC), and 30 percent of total time online via mobile.  Additionally, total time spent on social media in the U.S. across PCs and mobile devices increased 37 percent to 121 billion minutes in July 2012, compared to 88 billion in July 2011… consumers’ time spent with social media on mobile apps and the mobile web has increased 63 percent in 2012, compared to the same period last year.”

The report also found that “Pinterest emerged as a one of the breakout stars in social media for 2012, boasting the largest year-over-year increase in both unique audience and time spent of any social network across PC, mobile web and apps.”