Take a random guess at how many monthly users are active on Instagram. 4 million? 100 million? You're way off. The answer is a massive 300 million, that's right and that's a good platform to make real money. Put those numbers into perspective, it's more than Tumblr, Snapchat or Twitter--- and it surpasses Pinterest's 70 million by a colossal margin. In 2014 alone, Instagram grew by about 64 percent in terms of active users and became one of the fastest...