Who uses David Karp's microblogging site Tumblr? To us, they are trustafarians and their hangers-on — men with beards and thick glasses, girls with rainbow leggings and bangs. They are Sanfrooklyn's creative types and those who dress like them. Or — according to David Seger's Tumblr: the documentary, embedded below — they are "the dumbest babies of them all." We take exception to this as a Tumblista ourself, though we can't deny a sad correlation between our self-worth and the number of those who follow us.