Instagram hit 300 million active users on Wednesday, a total that puts the service in rare company as one of the world's largest social networks.
So how, exactly, does Instagram stack up?
There is no perfect measuring stick when it comes to comparing the size of social network-like services, but there is a generally accepted standard: Monthly Active Users. That is, the number of people who log into their account during any given month.
The MAU yardstick is used by all the major player...