Los Angeles has become a magnet for e-commerce companies since ShoeDazzle introduced its subscription service in 2009. This new wave of shopping websites relies heavily on the power of social media to market its wares.

So a local startup has been thriving by providing e-commerce companies with tools to tap into social networking.

Social Annex in Marina del Rey offers products and services designed to help shopping websites get their customers to share purchases on Facebook, Twitter, Google Plus and Pinterest. The company also provides tools to track social campaigns.

Since launching publicly last spring, Social Annex says it now reaches more than 500 million consumers and drives more than $10 million in new revenue for its clients each month.

Al Lalani, the founder of Social Annex, said the company now has more than 100 e-commerce customers, including electronics retailer JustDeals and women’s fashion retailer Cache.

Social Annex specializes in small online retailers that don’t have the ability to market via social networks on their own.

“The problem is that they don’t know how to do social,” Lalani said. “They want to make their site as powerful as a ShoeDazzle.”

Investors include Kamran Pourzanjani, founder of PriceGrabber; and Brian Lee, co-founder of ShoeDazzle, Legalzoom and Honest Co.

The company, which has 70 employees, raised an undisclosed round of funding last year to bring in additional e-commerce experience. Pourzanjani also sits on Social Annex’s board.

Eric Manlunas, co-founder and managing partner of Siemer Ventures, which has invested in Social Annex, said the company has tapped into a growing need for social marketing.

“Social Annex has started growing and continues to grow,” he said. “I’m a firm believer that e-commerce is here to stay. The good sites really have to start marketing deep down into these social networks to acquire customers.”