You only need to have access to both domains to get it to work. Or, basically that you can add a script to both sites. Its an old trick but I only recently needed to use it.

http://css-tricks.com/cross-domain-iframe-resizing/

As for standards – I personally care about them and tell my clients validation is a good for checking if the site is well done (doesn’t apply to cutting edge sites). Most of sites created still don’t use HTML5 I guess so there’s no reason for them not to be valid.

As for myspace – yeah, last resort, although I doubt people have such bandwidths to use it like on the video.

Kevin: so your find makes it possible to make cross-domain XMLHttpRequest calls, correct?