The comment you replied to has no DOCTYPE.

Therefore it is not XHTML.

It's not even HTML. It's quite obviously just an HN comment and not subject to the syntax rules of of XHTML or HTML.

So, your complaints about the tag formatting are unfounded.

The comment I replied to wasn't any valid format at all. What makes you think my reply wasn't in jest? Because it obviously was. People just want to nitpick my obviously humorous reply (which is actually fine up to a point as my humour was nitpicking so getting nitpicky about the nitpicking is valid too).

You are taking this far far too seriously.

I'm sorry my humor detector wasn't working as well as it should have yesterday. Writing doesn't have the nuances of personal conversation, and it often happens that something that was intended as humor doesn't come across that way.

I've been in your shoes here a few times, when I've posted something that I thought was obviously humorous and people took it seriously instead. It's usually happened when I avoided putting in a :-) because I felt like that would ruin the joke - and instead leaving out the :-) ended up ruining the joke.

So, peace, bro, OK? :-)

You're a better person than I, Stratoscope.

Oh I get it. You think XHMTL is the new hotness and HTML5 is the "old depreciated version". I guess I would have suspected that if I was browsing with cutting-edge IE6 instead of this crappy old Chrome 29.

Something can be both XHTML and HTML5. They're compatible. But, yes, all websites written today should be compatible with both. Writing to the quirks in the HTML format just make people look incompetent (particularly as no quotes means certain characters cannot be used in the value, which is a nice bug waiting to happen).

So by all means keep writing your low quality quirky HTML and when it breaks in the future don't come crying to me. I prefer keeping my HTML both well formed and XML valid. The fact that writing strict HTMLs makes it much easier to automatically detect errors and typographic issues is just a huge bonus.