BR> I know for a fact that Yahoo blocks Firefox on IPv6, they may even BR> redirect you to a non-SSL page that reflects such. Yahoo claims that BR> SSL on IPv6 for Firefox has security issues thus they deny access to BR> their site because of it. Now whether or not that's factually true is BR> another story when you consider they've been cracked twice. Yahoo is BR> the only site I've had an issue with being blocked.
I don't visit Yahoo but I believe you. Whenever you hear of someone doing some really weird and bizarre things, there is a reason to believe.