A while back, I received the following e-mail from a colleague:
This is an intervention.
The <q> element should only be used for quotations. To ensure correct usage of the <q> element, always use the "cite" attribute when using a <q> element (or a <blockquote> element). If there is no "cite" attribute that makes sense, then <q> is the wrong element.
I think we need to have more interventions like that on the Web. If you look a page's source and wince at the <table> elements used for layout or the gratuitous use of <div> elements, send the author an e-mail. Don't just squirm, do something about it. And certainly, certainly write good code yourself.
Disclaimer: I don't admit to writing 100% semantic code, but I know I've improved over the years, certainly due to hints from friends and colleagues. I also know that my current site isn't very semantic and I hope to fix that at some undisclosed point in the future when I move away from a canned theme.
PS: Naturally, I put the above quotation in a <blockquote> element. I can't cite the source, since it's from a private e-mail. Is that so wrong?
