Real KOMs (i.e. actual mountains or reasonably long and steep hills) are a decent measure but I hear an awful lot of whinging about non hill segments.

I was in Spain a couple of years back and they had a pre-cursor to Strava on one hill (Coll de Rates near Parcent). At the bottom of the hill you took a paper card and got it time stamped in a machine. You then ascended the hill and time stamped the card in another machine at the top of the hill and deposited it in a box. Once a week a volunteer would collect all the cards and post them on a website. (Stoppomat Startseite)