Not reading all these pages to see if this has been mentioned but here's my complaint:
No HTML5 support (WebM / VP8)
1 - Go to http://www.youtube.com/html5
in the Steam overlay's browser.
2 - Notice it says HTML5 is not supported.
3 - Going there in standalone Chrome yields the right result (Testing it now. Works perfect.)
Not having HTML5 compatibility is a MISTAKE. Valve should be going in this direction.
I have been talking to the people on Gmodtheater to find out more on Steam/Source and the HTML5 compatibility issue. I'd like to know the technical reasons why I can't do HTML5 on their server.
Here's the forum thread on the subject:
I'm dying to get rid of Flash.
Can anyone provide more information?