Perhaps I've been living in a standards-compliant web-design bubble. I've always been aware that one had to design around and account for odd quirks in page design when making sure websites look just as good in Microsofts Internet Explorer as they do in Chrome, Firefox, and Safari. I've even run across a few business banking sites that absolutely require Internet Explorer in order to manage the add-ons and check scanners.
That said, I think today is the first time I've ever seen a customer support site, even for a windows-centric product, that not only "required" Internet Explorer, but was utterly and completely unusable in any context without it. Unusable as in you could not even look up knoedge base and support articles.
Lest you think I'm kidding, check out the support FAQ page for the customer support portal for sage software. Under the question "What are the supported internet browsers for the Sage Customer Portal?":
Internet Explorer is the supported internet browser for use with the Sage Customer Portal.If you use Firefox, Chrome or other browsers and encounter issues, we recommend using Internet Explorer instead.If you use Internet Explorer 8 or 9, click the Compatibility View button to the right of the address bar to avoid potential issues. To permanently enable Compatibility View for the Sage Customer Portal, go to Tools > Compatibility View Settings and click [Add].