Hi all,
W3C Validation was introduced in order to create synchronization between various web browsers. However, it looks like search engines are giving advantage to those websites which are W3C validated.
Take for example, each and every page of wikipedia, can be validated through W3C validation tool available at
The W3C Markup Validation Service.
Wikipedia also gets updated regularly, thus getting ranking preference from various search engines. Content ( unique/fresh) has played in important role in success of wikipedia, but we would like to stress that W3C validation might have helped wikipedia to score higher rankings on both Google and Yahoo.
Google and other search engines are delivering higher rankings on the basis of combination of various factors, rather than any single factor (i.e back links, on-page, off-page optimization).
However this was my personal observation. Anyhow I would surely look forward for your inputs.