Actually, a lot of corporate pages with programming break with non-IE browsers. Like, HTML is the standard, and the most used browser is IE, so if we use the IE special hacks, then it's better than standard, right?
To be quite honest, I haven't read that on browsers, but programming. An API to some low-level industrial stuff was provided with interfaces using Microsoft's classes and other stuff like that, explaining that "C is the standard, and most computers run Microsoft's stuff, so when we use API & headers designed for Microsoft's compilers & IDE, we're doing better than standard". So, a thinly veiled "go buy Visual Studio if you want to use our stuff". Luckily, despite that I've never seen it used for anything else, we actually had the software. Parts of the API programming were rather outdated for Visual Studio, though, and I had a fun afternoon debugging the software, until I figured out that the default compiler options in Visual Studio were the reason why the program wasn't working. (The API used the approach of defining byte integers as chars, and when the integer value was > 128, the default compiler options did a character set remap... which meant that when some "small integer" had a numeric value beyond the original ASCII set, "funny" things happened.)