I'd say there would be a difference between younger people reviewing an application and older people especially given the generational divide in technological savvy, so to speak. I mean, if I were reviewing someone's grad school application, I would at least check to see if they had a FB - if not, I wouldn't hold it against them but would be curious if they were antisocial which would be elucidated at interviews, visits, etc. But then again, many grad students tend to be antisocial anyway. But I also know older people who have iPhones but refuse to use it for any other purpose than for making and taking calls (no texting either!). There isn't any box a reviewer has to check off noting whether you have a FB or not but the biases I'm talking about are more subconscious and more prevalent in the younger generations than in the older ones. These biases start to matter when you notice that admissions can be a "gut feeling" game on whether to admit this qualified applicant or that one. But then again, that would be individual-specific.