(I'm the author of the article.) Today, it's clear that text/html has won over application/xhtml+xml and JSON has won over XML for most (non-enterprise) non-do

(I'm the author of the article.) Today, it's clear that text/html has won over application/xhtml+xml and JSON has won over XML for most (non-enterprise) non-document uses. But back around 2003..2009, there was no shortage of people who advocated in favor of XML and got it wrong when writing it by hand or when generating it with text-based templates. Philip Taylor (not to be confused with Philip TAYLOR) was one of the regulars on the #whatwg IRC channel around 2007..2009. He had a hobby of trying to get XML advocates' systems to produce ill-formed output. He pretty much succeeded every time. IIRC, he even found a bug in Validator.nu's XML output, even though Validator.nu practices what I preach in the article. The easy way was to supply user input that contained U+FFFE and watch the output blow up with the Yellow Screen of Death when U+FFFE was echoed as-is. Unless you have a templating system designed with the warts of XML in mind, this will happen. (A proper XML serializer has to scrub the characters that aren't allowed in XML, as seen in https://hg.mozilla.org/projects/htmlparser/file/dd08dec8acb7/src/nu/validator/htmlparser/sax/XmlSerializer.java#l419 https://hg.mozilla.org/projects/htmlparser/file/dd08dec8acb7... .) He even found a bug in Tim Bray's code that was written to make the point that it's possible to generate XML correctly... (https://lists.w3.org/Archives/Public/www-archive/2009Mar/0060.html https://lists.w3.org/Archives/Public/www-archive/2009Mar/006...)