[DISCUSSION] A simple way to support X-Frame-Options: ALLOW-FROM

This evening I got a question on an Italian support site because a kind of stupid "social news" whatever website uses frames to show pages around the web and "promote" the websites (well, it's more promoting itself, but... heh)
So I googled a bit and discovered the ALLOW-FROM option:
http://blogs.msdn.com/b/ieinternals/archive/2010/03/30/combating-clickjacking-with-x-frame-options.aspx
It's not yet supported by some browsers (probably only [Chrome](https://bugs.webkit.org/show_bug.cgi?id=94836) and Opera now I suppose), so it may be tricky.

Opinions? (Also on the implementation that is a bit lazy... :innocent: )