Shoppers signed into retailer web sites using their Facebook log-in, known as Facebook Connect, are roughly nine times more likely to share content on the social network than other consumers, according to a new report by social commerce vendor Sociable Labs.

That behavior is extremely valuable about 30% of consumers on sites that use Sociable Labs’ social sharing applications log in via Facebook Connect. And when those consumers share they offer free exposure for brands, says Nisan Gabbay, CEO and founder of Sociable Labs. Every time a shopper shares a piece of content on Facebook, those interactions are seen by their friends in their Ticker, which features updates on what a Facebook user’s friends are doing at that moment, as well as on the news feed, which dominates the page a consumer sees when logging on to Facebook.com. The news feed displays the actions of a consumer’s friends.

Behind the stark increase is the fact that a Facebook log-in eliminates steps, most notably, the shopper having to sign in to the social network when he wants to share a piece of content, says Gabbay.

Moreover, having shoppers signed in to Facebook enables retailers to personalize their site with a list of the consumer’s friends, his name and other related content gathered from Facebook. That’s because when a shopper connects to an e-commerce site using Facebook Connect, he grants the site access to information about himself that he’s shared on the social network, such as his list of friends, his Likes and interests.

 “The big benefit of social log-ins is that it makes the social sharing experience that much easier and more compelling for the consumer,” says Gabbay. 

Sociable Labs study is based on data gathered on 20 e-commerce sites using Sociable Labs’ social sharing applications between October 2010 and January 2012.