Poynter's Rick Edmonds, in a rambling review of the ten-trends sort, says "Measurement is easy" and adds "Actionable measurement is tougher."
I'll go way beyond that: Measurement is outright hard, and it can be dangerously misleading.
A good metrics system is a boon to any site -- for sales purposes.
But for analysis, beware. We don't know what we don't know, and serving up a bunch of dazzling charts, graphs and heatmaps is a good way to be led astray.