Do Search Engines Care About Valid HTML?

Do Search Engines Care About Valid HTML? Like most web developers, I’ve heard a lot recently about its importance.

I’ve read about how it makes your site easier for people with disabilities to access, more stable for browsers, and easier for search engines to index.

So, when I set out to design my most recent site, I made sure to validate each page. But then I started thinking—while it may make my site easier to index, does that mean it will improve my search engine rankings? How many of the top sites have valid HTML?

I decided to conduct a little experiment to gauge the value search engines place on HTML validation.

I started by downloading the handy Firefox HTML Validator Extension (which//users.skynet.be/mgueury/mozilla/), which shows a green corner on the page you are on if the current page is valid HTML. It shows a green check when the page is valid, an exclamation point when there are warnings, and a red x when there are serious errors.

I decided to use Yahoo! Buzz Index to determine the top 5 most searched terms for the day, which included “apparently,” World Cup 2006, WW, FIFA, Shakira, and Paris Hilton.

I then searched each term in the big three search engines (Google, Yahoo!, and BING MSN) and checked the top 10 results for each with the critical. That gave me 150 of the most important data points on the web for that day.

The results were particularly shocking to me—only 7 of the 150 resulting pages had valid HTML (4.7%), 97 of the 150 had warnings (64.7%), and 46 of the 150 received a red X (30.7%). The results were largely independent of the search engine or the term.

Only 4 out of 50 results (8%) were validated by Google, 3 of 50 (6%) by MSN, and none by Yahoo! The term with the most valid results was “Paris Hilton,” which appeared on 3 of the seven valid pages.

Now I realize that this isn’t a completely exhaustive study, but it at least shows that valid HTML doesn’t seem to be a significant factor for the top searches on major search engines.

Even more surprising was that none of the three search engine homepages validated!

Also see:W3C Compliance & SEO

How important is valid HTML if Google, Yahoo!, and MSN don’t even practice it themselves?

It should be noted, however, that MSN’s results page was valid HTML. Yahoo’s homepage had 154 warnings, MSN’s had 65, and Google’s had 22. Google’s search results page not only didn’t validate, but it had six errors!

While perusing the web, I also noticed that immensely popular sites like ESPN.com, IMDb, and MySpace don’t validate. So, what is one to conclude from all of this?

It’s reasonable to conclude that at this time, valid HTML isn’t going to help you improve your search position.

If it has any impact on results, it is minimal compared to other factors.

The other reasons to use valid HTML are strong, and I would still recommend that all developers begin validating their sites.

Don’t expect that doing so will catapult you up the search rankings right now.

# Do Search Engines Care About Valid HTML?

Also see: AI Website Builders. Are There Any Disadvantages?

Post excerpts from Adam McFarland, owner of iPrioritize

ALSO SEE:
Validation Isn’t Everything
Like it or not, the industry often produces terms that become buzzwords. When this occurs—and it happens across the board, and web development is no exception—the terms can become diluted, even ambiguous.