According to a recent study by Monetate just under a half of all US consumers prefer to use a social log-in when creating a new or guest account on an e-commerce site.
Facebook was by far the most popular with 60% of US consumers preferring to log in through this platform. LinkedIn was the least popular at 7%
Product reviews figure highly on social media habits with 68% of consumers preferring to use social media for this purpose.
Being able to comment after signing on using social media also increases the time exposure a site has. Consumers who can't sign on and comment or share spend two thirds less time on a site compared to those that can.
One of the big attraction of a social log-in is that it is rapid and this increases user adoption. Spamming is also reduced as social networks are rigorous in eliminating duplicate accounts and auhtenticating people who sign up.
If you are not sure how to integrate social log-ins into your site you might consider using a third party service such as Gigya.