Your interview doesn't begin when an employer calls you. It doesn't begin when you walk into an office. And it certainly doesn't begin after you've done all the talking.
It likely begins before you even know it, through a simple online search to check out your presence. Essentially, you’re being “interviewed” online through your social networks — before the background check, before the phone call and before you have any sort of conversation with a potential employer.
Read more at: http://mashable.com/2013/04/20/social-job-interview/