According to U.K.-based TrendStream’s Global Web Index, the number of active Google+ users in the fourth quarter of 2012 was 343 million. Facebook is the largest social network by far, with roughly 700 million active users and nearly 1 billion total accounts.
Put another way, 51 percent of the global Internet population visits Facebook monthly, compared with 25 percent who use Google+ each month, the report said.
YouTube, which is also owned by Google, is the third-largest social network. Twitter ranks No. 4. It was the fastest mover in terms of active users, growing by 40 percent, to 288 million active users, from fourth-quarter 2011 to the fourth quarter of 2012.
The Global Web Index measured active users, ages 16 to 64, meaning they’ve used or contributed to the social network in the last month.