When you do a normal search on Google (or any other search engine) you’ll notice a very interesting phenomenon: the leaders of the search results don’t have the most beautiful sites. Then if you take a closer look and compare them with the sites situated on lower SERPs you will also see that the leaders of the search have more content, which also happens to be pretty relevant for the keywords you used.
For many of the website owners who invest a lot in custom web design this is frustrating. It becomes even more frustrating when they learn that the designs they got for such a high price are not SEO ready and they need HTML code validation.
Then we have the debate between SEOs who say that valid HTML is very important, SEOs who say that the search engines don’t care about such an issue, and designers who embrace this last opinion because they don’t want to go the extra mile and do the time-consuming code validation. The website owners then go on all the competitors’ sites and start checking them for valid codes. In most of the cases they grow to learn that many of these sites don’t validate, but they still rank well. For now.
Let’s think realistically about it: sites that validate are created by professional web coders.
That means they have a better quality than sites with hundreds of HTML errors. Because the search engines cannot see the design, but they read the code, it is only logical for them to like clean codes. That’s the quality they are looking for. And that gives you “trust” points in the “eyes” of a search engine.