When users on the web are asked to log in to a site, they most often choose Facebook over Twitter, LinkedIn or Google rather than registering anew, according to data from Janrain, which tracks social logins.
Facebook has become hugely dominant as the social login of choice but Google gained some ground in Q1 2013, Janrain reports:
During Q1, Facebook did lose ground to Google for the second consecutive quarter, dropping in popularity from 49% during Q4 2012 to 46% in Q1 2013, while Google’s share of social logins ascended from 31% to 34% during the same period.
Here's the chart: