Foursquare, a social service that lets users update friends about their locations through their mobile phones, recently got a $20 million boost from major investors, including Silicon Valley legends Marc Andreessen and Ben Horowtiz.

Foursquare, a social service that lets users update friends about their locations through their mobile phones, recently got a $20 million boost from major investors, including Silicon Valley legends Marc Andreessen and Ben Horowtiz. The social platform has grown at a record pace and it stands to expand further with these funds.

The service has accumulated nearly 1.8 million worldwide users in its first year, according to the foursquare blog. The funds it has secured will be used to make it easier for businesses to use the tool. More employees will soon be available to handle users’ requests, and foursquare plans to offer scalable tools for brands. The service is also looking to develop new ways to help business partners engender loyalty.

Foursquare’s potential to run campaigns that will increase customer loyalty was part of the appeal for Andreessen Horowitz. In his offical blog, Ben Horowitz explains the investors believe foursquare is unique in its ability to turn users into a business’ sales force.The firm believes the service will capture the attention of a “huge portion” of the more than 4.6 billion people who have mobile devices.

“We are very excited about foursquare’s ability to make money in a way where all parties win: users, merchants, venue owners, brand advertisers and more,” Horowitz wrote. In fact, a number of companies are already capitalizing on foursquare’s popularity to promote their brands. Check out the latest Verizon ad on Youtube, which indicates the move to monetization on the platform is viable.

Andreessen Horowitz was impressed with foursquare’s explosive growth, which it claims is happening faster than it did for Twitter when the microblogging site was at this stage.

Notably, Twitter has also revamped its location-sharing capabilities with the launch of Twitter Places. It remains to be seen which service will have a stronger appeal to consumers, but foursquare and Twitter together advance the mobile marketing industry.

Katherine Griwert is Brafton's Marketing Director. She's practiced content marketing, SEO and social marketing for over five years, and her enthusiasm for new media has even deeper roots. Katherine holds a degree in American Studies from Boston College, and her writing is featured in a number of web publications.