Ok so i understand that getting to the top of the throat of the world is tough, u need some shout to do it, which is it by the way? Also i was curious is there a quest that u need to go up there for or is it just a fulfilling accomplishment.

You get Notch's Pickaxe (Minecraft reference) and you get to see the White-Gold Tower and Red Mountain.

You really want spoilers? Okay then.

You use the Clear Skies shout to make your way to the top, and once there you meet Paathurnax, the leader of the Greybeards. He's a very old dragon, the one that helped the ancient Nords defeat Alduin. He established the Way of the Voice and teached it to the first Greybeards. Now he lives in solitude atop the Throat of the World. He teaches you how to focus on one of your shouts, making it more powerful. You also get part of the Fire Breath shout up there.

There's plenty more but I'll let you find all that out yourself.

You will need to go up there as part of the main quest line, you will know when it comes.