As a merchant, can you imagine all of the benefits with allowing your customers register with Facebook or Twitter?
Customer Information - This allows you to capture the email addresses before they ever get to checkout and other additional personal information that your customers don’t mind sharing, but definitely don’t want to have to fill out another form for it.
Sharing is Good - By embracing social media, you’re tapping into a wealth of shareable products. Imagine making it super easy for your customers to share that neat thing that only their friends would understand!
Request more than the default access - With just a little bit of configuration you can map their birthday to a user registration field that gets saved to your system. The potential of useful information is only limited by your imagination!
Read more at CommerceGuys.com