It appears like IDN
is still something quite unusual. IDN stands for 'internationalized domain name', and with it, you can create URLS and domain names with non-ascii characters. Like for example www.raumträume.at
: Internally, this gets converted to www.xn--raumtrume-02a.at, and actually, some older browsers even show this domain instead of the one you entered.
Unfortunately, depending on your local language settings, even very popular apps like the Internet Explorer still cannot handle this today. (Just tried this out with IE 8 on an english Windows). Another example: Google Analytics. If you tell it to track your website with non-Acii-characters, it will pretend to do this, but unfortunately, it will never show you any visitors coming to your site. It will never show you any error and even report your tracking code as successfully installed. I needed two days to figure out why this didn't work.
IDN support is something important, and although it is existing now for 8 years already, still today, support for it isn't there yet. I guess one of the reasons might be that lots of developers don't even know of its existence. But I hope this will get better soon, as more and more people are using these domains.