Hi, It is really till now not clarified that the W3 validation that we do is really a waste of time or It gives some benefit to our site. Since in many cases I have seen some sites rock the web in terms of SERP and is not a valid HTML or XHTML Document. See the case of "web design" (without quote) keyword in google.com, here you will find the site at no 2 is not a valid HTML or XHTML Document but ranks well in SERP. In the same way you type "seo forum" (without quote) in google.com and you will find forums.seochat.com ranks no 1 with an invalid markup. So do we really not waste our time in doing validation, since by doing this we try to make our web page search engine friendly, and a site if rank well in major search engines means that it is SE friendly in whatever way the search engine spider looks at it.