Funny, I thought HTML was a markup language. The article says HTML is (or can be) both source code and object code. I say it's neither. HTML isn't the source code for some application or piece of software, and it's not the application or software itself. It doesn't tell a cpu what to do, it tells a browser what to show.
It does not make sense when one of the most important readers of your site is effectively blind: Googlebot.
I've used both approaches, good semantic markup and sloppy made-for-IE. Choosing good semantic markup has never come back to bite me in the ass. Sloppy markup has gone two ways, more often been a time saver and soon thrown away, but sometimes come back as a horrible thing to maintain and extend.