May 31, 2011 12:41 GMT  ·  By

Airbnb is said to be very close to closing a massive funding round, valuating the company at $1 billion. That's a huge increase over any previous estimate and a lot more than it was worth during its last funding round.

Airbnb managed to spark the interest of some of the hottest venture capital funds, Andreessen Horowitz is said to be leading the round, according to TechCrunch, and the Russian DST is also participating.

The startup is raising $100 million in the latest round, a significant increase over the last round when it raised $7.2 million. In total, the company has managed to get this far with a little over $7.8 million, since launching three years ago.

Airbnb has been making a name for itself as an innovative way of finding a place to stay in a foreign city or renting out a spare room once in a while.

The simple concept, of getting those looking for a room, but not necessarily an expensive hotel room, in touch with those looking to make some extra cash and maybe meet some new people has proven quite attractive and the service has expanded world wide.

In the last year alone, it grew eight times and 1.6 million rooms have been rented via Airbnb. But its expansion needs fuel and this is where the new round comes in. Though, considering it's been doing great so far on so little, $100 million may seem excessive.

Besides its growth, Airbnb's story as a company is an interesting one. When it started out, no one believed a business could be built on top of the concept. Plenty of investors passed on the opportunity only to later regret it. In fact, Airbnb has become somewhat of a cautionary tale in Silicon Valley which investors use to point out that there are opportunities in even the most counter-intuitive ideas.