Also, not a good idea where every third person is youth .
> most people under 20 do not have much interest in Facebook at all. They have accounts of course, but very few are very active.
That is true for mostly US/Europe - Asia is a clear exception where Facebook is still very much the medium of choice and snapchat etc haven't even come close to replacing it.
Enzymes are things invented by biologists that explain things which otherwise require harder thinking. -- Jerome Lettvin