"For these sites ... critical mass is crucial: you won’t visit a site if no one else is using it." This is not as true for Pinterest, which has a standalone us

"For these sites ... critical mass is crucial: you won’t visit a site if no one else is using it." This is not as true for Pinterest, which has a standalone use as a nice visual bookmarking tool - my wife uses Pinterest heavily (mostly for cooking and fashion) and isn't engaged in the social aspects at all.