Instagram Picks Up 10 Million New Users In A Few Days: Sky's The Limit?

A billion dollars. That sum can buy a lot of things, including a photo-crazy social startup called Instagram. Just days after Facebook plucked down a huge sum of cash to grab the company and its employees, millions more are flocking to it in order to see what the hubbub is all about. Instagram already had around 30 million users before Facebook did the deed, and now the total user count is at 40 million. It's not surprising given that Android users can now get in on the fun, but still, 10 million in just a few days? It took nearly 18 months to hit 30 million.

Obviously, Facebook is keenly interested in having these users eventually become active Facebookers, as there's no real cash model yet for Instagram alone. Perhaps Facebook is now coyly smiling thinking about all of those folks who suggested that the company overpaid. If we've seen a 10 million user spike in just a few days, what'll happen when Instagram is integrated into Facebook's mobile apps for BlackBerry and Windows Phone?  We're just speculating, but still, the dollar signs are starting to add up.