In a redesign I worked on using a content management system, many of the content owners were in the habit of using HTML shortcuts, copy and pasting special characters (instead of the HTML codes for them), and other techniques to write their code.
In the latest redesign, the CMS programmers decided to convert to valid XHTML so that they could convert the site more easily to a data driven site - with XML backend and a database. Unfortunately, when they planned the redesign, they did not count on an extra 4 weeks of development time spent fixing the problems caused by the content team.
And now, a year later, they are still dealing with comments along the lines of "it used to work even if I didn't close my paragraph tags" and "explain why I can't just paste in © and I have to use © instead?"
If you're a content writer - it pays to learn correct techniques. Even if it "works" when you use shortcuts, that doesn't mean you won't spend time in the future fixing those shortcuts.
If you're a site developer - teach your content authors correct techniques. If you don't, in the future you'll have to write code that supports their mistakes.
