I have seen people do everything from create new worlds, to making the colors mesh better to make it look more realistic. I personally haven't tried modding, so I'm wondering what the extent of modding lets you do. Can you make quests? Can you create entirely unique worlds? Can you create new unique dialog? answer plz

We have the same tools the developers used to make the game. We can do anything that's ingame, as well as our own versions of it. Anything. New dialogue, people, places, quests, items, enemies, weathers, meshes, textures. Anything. (Except a few very things that are hardcoded and we cannot alter.)

Namely skills and actor values, some UI stuff and how the engine itself actually works (like don't expect to be able to add DX11 graphics or a 10mm Pistol easily). Other than that, go make whatever you want

sounds epic

are there set models? like can you pick to have a spider or do you have to fabricate it?

You can create custom meshes and textures if needed (takes a lot of time however). Most people tend to re-use Bethesda's meshes however, anything in the base game you can use and modify.

so your saying you can use whatever bethesda uses, and you can also use what you want to use... So your saying that you could make a goblin v falmer war?... I think I might by the creativity kit... one last question, is their an introduction to this? and is code based, and would it take a fair understanding of software to use it?

You'd need to create a goblin mesh and texture which would be highly time consuming and the learning curve for meshes is pretty high. However yes, it's entirely possible.

It's a bit of everything. You'll need to learn Papyrus (the scripting language) if you want anything more than a basic house or dungeon done, however you'll need to learn the CK too, it depends what you want to do.

The http://www.creationkit.com would be a good place to start. Don't expect to be able to make an expansion pack overnight mind. It takes a long time to learn.

well... i got about 5 years until the next TES(judging on how long it took from oblivion to skyrim), so I got nothing but time to learn how to mod, you've been a great help, ty

Also, there is a thread at the top of the Creation Kit form for Video Tutorials. If you want to actually see how something is done and not just read about it.

Not a problem. We're always here in the forum if you get stuck or need some advice