The company’s post claims that “more than 170 million people have upgraded to Google+,” a figure that almost doubles the figure that Google threw out for Google+ in January. Assuming the self-reported figure is true, that means that G+ is now the third-largest U.S.-based social network in the world.To be sure, G+ is still miles behind Facebook’s 850 million users and Twitter’s 500 million, but it appears to be comfortably ahead of LinkedIn’s 150 million, though LinkedIn’s figures are from February and have likely increased since then. A LinkedIn rep declined comment on the company’s current user base size.So, does that mean that Google+ is now the number three social network?

via Is Google+ the No. 3 Social Network? Depends How You Measure It.