This is an important concept:

Since online outlets started tracking “read depth,” we know that most readers get through about 50 percent of an article before leaving — and about a third never get past the headline. That makes news economics a volume game, both in terms of content produced and total readers needed, as publishers attempt to make up for their readers’ superficial attention by throwing more headlines and more content at them.

via Why a Facebook cofounder’s magazine is crumbling, in two charts | VentureBeat | Media | by Gregory Ferenstein.