Do search engines favor websites that are using CSS more that sites using tables? And how important is it SEOwise for your website to be w3c validated? thanks.
Of course yes, examine the code because as you have read the coding structure of the tabled sites, it may have your head spin because of the complexity of the code. W3c is not that important to SEO, but it is important in some browsers because mobile apps and other browsers want XHTML/CSS valid sites.
I don't know if Google directly favors CSS websites, I don't think it can see that... However, having a good HTML/CSS code is much better. It is lighter, better structured, etc. So you already benefit from it. P.S. not all HTML/CSS code is good... there are good coders and there are bad coders.