Seventy percent of parents say they keep tabs on the social media activity of their kids, according to a survey by the Annenberg Center for the Digital Future. Forty-six percent of those parents said they had the password to their kids' Facebook account. The 30 percent who said they didn't monitor their kids' activity online had several reasons for staying away. Nine percent said that their limited knowledge of the site kept them from being able check up on them even if they wanted to.