I was just thinking, maybe they didn't mean it literally, but the GI article said everything you can see is traversible. Could this mean some strange method (such as random fog) instead of invisible barriers? Because honestly, I think anything else would just seem excessive and silly, and break immersion more than the barriers.

I think they just put that in to exaggerate on how big the world actually is.

Maybe they meant if you see a mountain or hill you can go to the top and/or go anywhere without invisible barriers like in Fallout: NV.

I have to wonder how big it will be compared to past games....not Daggerfall of course which was bigger then the size of the U.K, it would be nice if its bigger then Oblivion (more exploration)

ya they'll probably just rely on Skyrim's natural borders