I am using Family Safety web filtering in whitelist mode.  YouTube is not in the list of allowable sites.  Visiting youtube.com directly results in it being blocked, but if I go to this site:

scroll down to Community Activity and click the "Videos" tab, the YouTube video will play.  The YouTube link appears in an iframe on the page.

Is there other content that doesn't get blocked because it's in an iframe?
 
I am using the Chrome browser - haven't tested other browsers.
There is some advertisement in the messenger loop that is causing the client to eat all available CPU and memory. This is happening to everyone in our office (windows XP, vista, 7). We're also running different versions of IE for the IFRAME (ie 6,8,9).

Please QC the crappy javascript your advertisers use.