I was just saying "AJAX" as to me it didn't look like a straight forward iframes implementation.
The fact you say the SCM player is doing some jiggery pokery is probably what I was seeing.
Technically there are some methods out there (jquery lets you do this pretty easily iirc) that let you update the URL in the address bar like in the case of using hashbang tags etc.
I'm not sure how well search engines handle it though.
To add more food for thought look at this Google result for The Lowry:
http://www.google.co.uk/search?aq=f&gcx=c&ix=c1&sourceid=chrome&ie=UTF-8&q=the+lowry
See how you get direct access to "contact us" and other useful pages that Google has found. This is the kind of useful contextual links that power users expect to see and I'm not sure this kind of implementation will support.