Earlier quoted context omitted.
No, you're right. Portal is effectively iframe without all the security protections.
I don't understand the cynicism people have for this idea. All they did was say "wouldn't it be cool if you could have nice animations in between pages" and built a proof-of-concept. It's not a finished product. They aren't forcing it into a standard. It's a demo of something that would be cool. So why the heck are people opposed to that?
https://people.apache.org/~jim/NewArchitect/webrevu/1998/12_...