

Why does Google ignore HTML validation? - dennisgorelik
http://validator.w3.org/check?uri=www.google.com&charset=%28detect+automatically%29&doctype=Inline&group=0

======
kitcar
For speed - some elements necessary to validate a web page aren't necessary to
display the webpage correctly - hence discarding it results in a slightly
faster page load, without any negative effect on user experience (as
everything renders correctly)

