But when your client says they want a link or tag line placed at the bottom of the third column and you email the client and say, "Gee, I'm sorry... but the DIV and CSS used don't support this, you're going to find the client saying, "Look, do I have to find someone else to do this?"

You say, "No" ...because you want your money, and then go ahead and break every rule in the book.

The client that hires you to build his/her website, doesn't understand coding practices and limitations. All they understand is what they want.

The image/icon on the bottom of the website that takes you to the W3C validator to verify the site as Xhtml strict type document, doesn't mean a damn thing to your client.

And if you're only writing web pages that validate as W3C Xhtml strict, that you're not living in the real world.