When you hire someone to create a website for you, you basically view the end result. The aesthetic look and feel of the website can be achieved many different ways. For instance, someone might use a table layout. Another could do it without any tables. The possibilities are endless.

To the unsuspecting client, what you see is not always what you get. A poorly coded website can can introduce a few problems, notably speed and ease by which web crawlers (google, yahoo, etc) can index the website content. The World Wide Web Consortium outlines some standards for proper web design.

In effect, the standards separate web content from presentation. Adhering to standards is not only easier for the client to make changes but also for other companies and freelancers involved.