Zkuq on 05 June 2016
On platforms where there's no built-in functionality to voice agreement (e.g. upvote system), 'this' is a natural way to do that. When someone has already said something really well, it doesn't make much sense to repeat the same in slightly different words. 'This' is thus also a way to save people's time so they don't have to read the same thing again and again.
