When your job is to get people to pay attention to you, why would categorize anything as less than the most important? Crowd-sourcing the importance might be better, but that brings us right back to a HN/reddit solution.
[1] http://en.wikipedia.org/wiki/Neil_Postman [2] http://en.wikipedia.org/wiki/Availability_heuristic [3] http://en.wikipedia.org/wiki/Public_Opinion_(book) [4] http://en.wikipedia.org/wiki/Jonah_Peretti