This actually predates emoji (and was mentioned in the article). In the early 00's we got the ability to use unicode characters in a domain name. The example I always like was Unicode Snowman ;-)
http://xn--n3h.com/ (Funny enough HN is stripping the Unicode Snowman glyph, so using the puny code version)
Was a great way to break websites. JavaScript used for client-side validation usually allowed it, but backend code often didn't understand unicode for URLs, and would usually choke somewhere and (fingers crossed) give you a lovely J2EE or ASP.NET error page with some helpful stack traces and version numbers
http://xn--n3h.com/ (Funny enough HN is stripping the Unicode Snowman glyph, so using the puny code version)
Was a great way to break websites. JavaScript used for client-side validation usually allowed it, but backend code often didn't understand unicode for URLs, and would usually choke somewhere and (fingers crossed) give you a lovely J2EE or ASP.NET error page with some helpful stack traces and version numbers