User blog comment:Jimeee/Skyrim 1.9 beta update adds Legendary difficulty and raises level cap (Updated Apr 8th)/@comment-97.106.15.105-20130321205928/@comment-3152761-20130321223507

Legendary Skills work like this: Once you reach 100 in that Skill you can make it legendary, reseting to 15 and removing the associated perks and allowing you to level it up again to 100 and make it Legendary again (Which allows for infinite leveling). Legendary can be put on a skill as many times as you can, all it does is allow you to have more perk points. FYI the new difficulty setting is ridiculously hard, for anyone wondering.