Is there a site that point out what the diffrent settings (rules) do or alter. I could find it for oblivion, but not for morrowind. I know a few, but it would be nice to have some sort of overview.

MW Scripting for Dummies has a section that explains what most (some are not verified) of the GMSTs do.
It's near the end of the document.

Thanks Pluto, I will check it out

You can also search Google for specific settings and usually find an answer... as I just learned.