I believe it falls under the Association fallacy (http://en.wikipedia.org/wiki/Association_fallacy http://en.wikipedia.org/wiki/Association_fallacy). The assu

I believe it falls under the Association fallacy (http://en.wikipedia.org/wiki/Association_fallacy http://en.wikipedia.org/wiki/Association_fallacy). The assumption is that because both designs share a common attribute they are both intended for the same purpose and therefore if one design is bad for a particular reason, the other design must also be bad for the exact same reason. This isn't necessarily true with Pinterest, which has a different purpose to Facebook, and therefore likely requires a different UI.