You’ll earn stat increases as well as Magic Find and Gold Find.
‘Diablo III’ was a very well received game, but as players complete it, they find themselves left without much to do. There really isn’t any end-game content besides the ability to farm gear while fighting frustratingly difficult packs of monsters.
The folks at Blizzard have heard the complaints and are making some changes for patch 1.0.4. In the upcoming patch, they’ll be introducing Paragon levels, which add basic stat improvements as well as 3% Magic Find and Gold Find per level. You can earn 100 Paragon levels, which means you’ll be able to reach the 300% Magic and Gold Find caps without having to invest in any gear, freeing you up to do more damage and take more hits.
There’s no word at this point on when the patch will go live.
Source: Game Informer