While it wasn't so clear at the time, the approximately $1 billion in cash and stock Facebook (FB - Get Report) paid for Instagram back in 2012 seems to have been a bargain.

Instagram has proven to be a social network not only users love, with more than 400 million monthly active users, but advertisers are loving it, too -- the company announced it now has more than 200,000 advertisers on the platform.

After opening up the platform to all businesses to run ads on in September 2015, advertisers of all sizes are coming in droves, with ads Instagram users say are working.

In a release citing a user survey from November 2015, the company said 60% of Instagrammers learn about products and services on Instagram, with three-quarters of them taking action after seeing the ad, be it visiting the advertisers' website, searching, shopping or even telling a friend.

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Instagram is seeing some spillover from Facebook, suggesting that advertisers see the benefit of the platform. On the company's fourth quarter earnings call, Facebook COO Sheryl Sandberg said 98 of the top 100 advertisers on Facebook also advertised on Instagram, showcasing the power of the visual-heavy platform.

Three quarters of its advertisers are outside the U.S., in more than 200 countries, suggesting that it's a global phenomenon and not just U.S.-based.

In 2016, eMarketer expects 9.5% of global mobile ad revenue for Facebook will come from Instagram, growing to 14% by 2017. Analysts surveyed by Thompson Reuters expect Facebook to generate $25.5 billion in revenue in 2016 and $33.8 billion in 2017.

Assuming payments revenue stays around 4% of global revenues (it was 4.7% in 2015), and mobile ad revenue is around 80% of advertising revenue, Instagram should generate roughly $1.86 billion in 2016 revenue and $3.63 billion in revenue in 2017, using eMarketer's 9.5% and 14% totals.

Not bad for a few pretty sunsets and some gym selfies.