This is what you see:
What makes me think that yahoo is misdetecting IE8?
In any case manually adding the site to the compatibility mode fix this.
You may think that both Yahoo and Microsoft will have look at one of the top 10 sites, don’t you?
Maybe this affect only the Canadian version of the site?
I’m surprised because this is the first site I found it doesn’t work. I was expecting some other sites to have problem but never Yahoo.
Notice that the compatibility button is not shown by default. Looking at the code behind I see this: