There's a lot of talk in the media about [Kevin Jorgeson and Tommy Caldwell's free ascent of the dawn wall of El Capitan](http://www.bbc.co.uk/news/world-us-canada-30793748). 

This wall has been climbed before, but this is the first time it's been free climbed. What are Kevin Jorgeson and Tommy Caldwell doing differently now that hasn't been done before?