Facebook has a significant fraction of the world Internet population (about 41%). Google has far less (about 6%?). Growing as fast as Facebook is great (better

Facebook has a significant fraction of the world Internet population (about 41%). Google has far less (about 6%?). Growing as fast as Facebook is great (better than growing more slowly) but the marginal effort to acquire a user is much higher for Facebook than for Google. You can't compare the growth rate of Google+ to Facebook any more than you can compare Google's growth rate to Bing.