How important is it to have a validated site?

Question

Many big website (google.com, apple.com, microsoft.com) are never validated. When the big shots don't do it, is there a reason why others should?

Answer 1

They are probably validated, but need to support older browsers (like IE6), so comptability-code is added.

Answer 2

Just because someone else doesn't, doesn't mean it's not a good thing. When you validate, you not only find out if your pages are well-formed, but you also track down bugs in your code, make the web pages easier to maintain and your code is more likely to work cross browser as well with future browsers. In addition to this, it shows that you take your job serious and that you have a good habit of trying to generate quality code.

Answer 3

Staying strictly within a known range of syntax (or technologies, in general) is good for optimizing maintenance costs, because all technologies you depend on (browsers in this case) are very well tested for the standard-conforming cases (subset of HTML/CSS/JS) only and are only randomly tested beyond.

Answer 4

w3.org provide a page dedicated to people asking just that question, it's here.

Of course places like Google and Microsoft are there to appeal and should all be consistent across browsers. The w3 does have some good points

Using standard, interoperable markup and stylesheets, on the other hand, offers a much greater chance of having one's page handled consistently across platforms and user-agents. Indeed, most developers creating rich Web applications know that reliable scripting needs the document to be parsed by User-Agents without any unexpected error, and will make sure that their markup and CSS is validated before creating a rich interactive layer.

When surveyed, a large majority of Web professionals will state that validation errors is the first thing they will check whenever they run into a Web styling or scripting bug.

Another very important point is maintenance. A strictly valid XHTML document as much easier to maintain than a bowl full of HTML tag soup. Trust me.

We must remember that the markup is there as a data format. The way a browser renders this markup is what's generally important to a user.

Do remember: household-name companies expect people to visit because of the name and in spite of dreadful websites. Can you afford that luxury?