2012 has been the year of startups. Some of the fastest growing startups in the world took the IPO route this year, including Zynga, GroupOn, Yelp, and of course, Facebook’s mammoth $100Bn IPO. As Marc Andreessen said earlier this year, “software will eat the world”. Given how fast some of the startups on our list are growing, Andreessen’s words sound all the more prophetic.

Let’s take a look at the ten fastest growing startups across the world:

1. Facebook
Facebook might have gone public, but it is still technically a startup. The company is less than a decade old and already boasts a market cap in excess of $50Bn. The Facebook IPO was the most storied tech event of 2012 and created over 1,000 new millionaires. The company had revenues of $1.26Bn in the third quarter of the year with over a billion users all over the world.

Facebook

2. Twitter
Twitter is the other social media darling that continues to attract users and stay relevant. Twitter is expected to bring in $259.9 million in revenue this year, up $139.5M in 2011. Of all the social media upstarts, Twitter is the most expected to go public within the next two years, with revenues touching $540 million by 2014.

Even more importantly, while Facebook’s growth is slowing down, and upstarts like Zynga and Groupon tanking after their public offerings, Twitter seems to be showing no signs of slowing down, with over 175 million registered users.

Twitter

3. Pinterest
Pinterest has been the runaway success story of 2012, growing faster than any startup in history. Perhaps more importantly, one study revealed that more than 70 percent of Pinterest’s users are there for shopping inspiration, which could spell big bucks for this fledgling startup.

Pinterest

4. Instagram
“$1Bn for a photo app?” This was the question everyone was asking when Facebook made the bold move of buying Instagram for $1Bn in April this year. And the purchase has paid off – Instagram continues to grow at an incredible pace. In May 2012, it had 50 million users. By September, this number was up to 100M, and continues to grow even more every day, making it one of the fastest growing startups in 2012.

5. AirBnB
The online holiday rental marketplace took off big time in 2012, hitting a market valuation of $2.5Bn. AirBnB connects homeowners with travellers, allowing them to rent out their premises on a daily, weekly, or monthly basis. With a slick product and a user base in the millions, AirBnB is among the breakout success stories of 2012.

6. RelayRides
RelayRides is trying to disrupt the multi-billion dollar car rental marketplace with its unique P2P spin on car sharing. Through RelayRides, anyone can rent out their car on a hourly, daily or monthly basis. With a million dollars in insurance and quality user-vetting processes in place, buyers have been lining up.

7. Fab
Fab.com is an online marketplace for designer items. After pivoting from a social network (Fabulis), the startup has seen tremendous growth, hitting more than $140M in sales within two years. With a market value in excess of $600M, Fab.com looks set to revolutionize e-commerce.

8. HipMunk
Everyone thought there was no room for improvement in the online flight booking space, and that Expedia/Priceline/Kayak had the market corner. HipMunk, however, thought otherwise. The new flight booking service has gathered millions of new users with its intuitive, hassle-free booking system. Founded by the co-founder of Reddit, HipMunk looks set to be one of the biggest success stories in the travel space.

9. DropBox
DropBox was among the first cloud storage service providers, and is certainly the most successful with more than 45 million users. With a market value in excess of $4Bn, DropBox leads the online storage space, although it has stiff competition from the likes of Box.net, Google and Microsoft.DropBox

10. Gilt Group
Flash sales sites have turned e-commerce on its head, and the Gilt group has led this revolution. With revenue in excess of $600M in 2012, Gilt is among the most successful web startups, and continues to grow strong even as daily deals platforms like Groupon continue to suffer.