Logging in through the likes of Facebook, Twitter and Google may be the easiest way to connect to 3rd party sites across the Web. Sure, it means we’re forfeiting heaps of data, but that hasn’t stopped the trend from nearly killing the traditional login process in just a few years.

Following this trend, Janrain has released a study powered by its Engage tool, which analyzed some 365,000 sites. Overall, Janrain found that Facebook accounted for 45% of social logins, while Google came in at 31%. Yahoo and Twitter collectively hold an 18% share of social logins, while LinkedIn, Myspace and a number of other sites account for the remaining 3%.

Screen Shot 2012 05 04 at 1.26.10 PM Facebook and Google dominate 76% of social logins, according to Janrain studyJanrain notes that “Facebook’s popularity for social login on eCommerce websites has declined moderately from 49% to 43% during the past two quarters. Despite the decrease, it still enjoys significant popularity, which can be partially explained by the explosion of social commerce during the past year. Yahoo!’s share of social logins on retail sites has plummeted since 2009, mostly due to Google and Facebook.”

Perhaps thanks to Google+, overall preference for Google has increased 2% since Q4 2011. As far as mobile apps go, Twitter has seen some strong growth, likely due to its iOS 5 integration.

Screen Shot 2012 05 04 at 1.29.08 PM Facebook and Google dominate 76% of social logins, according to Janrain study

As for actual sharing, Twitter continues to be the only network with a chance at fighting Facebook for the #1 spot. LinkedIn, Myspace and Yahoo follow, holding the #3, #4 and #5 spots respectively, far off in the distance.

Screen Shot 2012 05 04 at 1.42.22 PM Facebook and Google dominate 76% of social logins, according to Janrain studyThese stats aren’t particularly surprising, but it’s nice to see some actual numbers showing what’s happening, as they can help us predict the growth and decline of networks over time. We’ll keep a close eye on these numbers for future trends, as should anyone interested in this space.