But if you've been paying attention to shifting demographics, the results shouldn't surprise you.

Pew surveyed 1,802 Internet users, between November 14 and December 9, 2012. (There weren't enough Asian American respondents to draw statistically reliable conclusions.)

Twenty-six percent of black Internet users reported using Twitter, higher than Hispanics (19 percent) and whites (14 percent). The results are similar to Pew's report from 2011, expect the number of white users has grown.

But Pew also reported a similar breakdown for Instagram: among the Internet users surveyed, 23 percent of blacks, 18 percent of Hispanics,and 11 percent of whites reported succumbing to the new narcissism.

There was less of a racial discrepancy with Tumblr: 8 percent of Hispanic, 6 percent of white, and 5 percent of black Internet users reported microblogging. In terms of Pinterest: 18 percent of white respondents, 10 percent of Hispanic and 8 percent of black respondents use the service, although the most notable breakdown continues to be female Internet users (25 percent) versus males (5 percent).

A subtle hint to "new Internet" startups like the Svtle, Medium, and App.net's of the world: if this is how social networks adoption evolves over time, you might want to diversify your "alpha geeks."