Did you know that there is an online version of CSE HTML Validator?
A free service at OnlineWebCheck.com
) helps webmasters fix website syntax and other problems and be seen correctly by search engines. Most websites contain HTML syntax problems. Some of these problems can be severe enough to affect a website's ability to be indexed properly by search engines. Damaged or missing search engine listings can greatly affect the number of people coming to a website because many websites are discovered through search engines.
HTML and CSS problems can also cause trouble for visitors. While a website might look fine in one particular browser, HTML and CSS problems can make it look corrupted in another. This is especially important today because many people are using alternative web browsers like Opera and Firefox as well as mobile devices.UPDATE 2011-01-20:
Significant upgrade- OnlineWebCheck.com is now based on the professional edition instead of the free lite edition for better results including CSS checking!