Most critics believe Google+ is gaining popularity online, but at least one study figures Google's latest social experiment is growing at rates that rival Facebook's. The search giant's two-week-old social network, currently in a limited field test, reportedly grew by 350 percent between July 4 and July 10 from 1.7 million users to 7.3 million. Google+ is also set to hit 10 million by Tuesday and 20 million by the weekend, according to one study.
