Well, I must say I’m pretty surprised with the results of some research regarding validation errors… even the biggest sites have errors! As of today, here are some of the error counts for various web sites:

• Microsoft.com – 0 (surprise!)
• Google.com – 50 errors
• Whitehouse.gov – 63 errors
• CNN.com – 70 errors
• Monster.com – 185 errors
• eBay.com – 249 errors
• Yahoo.com – 275 errors
• Weather.com – 313 errors

I found this while developing our newest feature – a page where you can run tests on your web site. Check it out!