It could very easily be the case that Facebook's difficulty in popularizing friend lists was somehow path-dependent: e.g., FB users weren't using it from the be

It could very easily be the case that Facebook's difficulty in popularizing friend lists was somehow path-dependent: e.g., FB users weren't using it from the beginning, so users had a different model in mind. We agree, I am not saying that circles are hopeless just because they've already been tried. There seems to be a bogus meme propagating that Facebook doesn't have the functionality at all, though. You can do this stuff on Facebook if you're so inclined.