For a long time it has been possible to use chars such as æøåüöé etc. in .com and .net domains. However it is only possible to browse to these domains if you either own a mozilla browser, or have downloaded this IDNplugin to Internet Explorer.
Now, one whom uses Mozilla will get an all-around nice experience of browsing these domains since he will not notice any “Install this plugin” dialogs etc.
I myself was rather supprised to find out that mozilla supported this.
E-mail is another problem with IDN domains.
Webmails such as hotmail and a large amount of other webmails does not support sending to these types of domains, thereby if your primary domain is an IDN domain you are not likely to be getting a whole lot of email (and no spam?).
You can however send e-mail to IDN domains if you are the owner of Outlook Express or Outlook (not Outlook 2003).
Again the use of IDN domains in Microsoft programs is 100% dependent on the IDNplugin, Microsoft did show some interest in supporting these domains by default at some point, but then backed out – leaving the whole IDN concept dead in the water. Strangely enough Mozilla Mail/Thunderbird does not support the use of IDN domains in emails, yet.
Another problem is internationalization, since an English keyboard does not come with æøå on them they will find it hard to visit your site or send you email. It’s not very polite to require them to know the ALTGR + [0-9] combination for the chars.
I can understand why someone would want an IDN domain to be their secondary domain, since it’s a nice feature to both own rene.com and rené.com – but only owning rené.com would be silly, since e-mail support is rather non-existent with IDN domains.
Its popularity is largely dependant on e-mail, therefore I think Microsoft should get out of the starting holes and put some effort into supporting these new domains. So you don’t have to download some silly plug-in to use them as normal domains.
The whole concept seems to be somewhat broken :)
[ end rant]