You're probably familiar with the use of star ratings for routes. (For details on our community-generated route quality ratings read 'How do stars work?')
We've extended this concept to develop an indicator of crag quality.
We call it Crag Kudos. Basically we reckon that if users who contribute to the site earn Crag Karma it seems only fair that crags should earn Kudos.
Crags earn Kudos based on how often people climb there and how highly their routes are rated. In other words it's basically a combination of the number of ascents and quality ratings (with a few weightings and other smarts thrown in).
As you browse the index the 'Classic Crags' listed at the top of the left-hand column will be the ones with the highest Crag Kudos for that region.