it just means that the coding on that page is html valid, some people think it helps with seo i personal dont, i spent ages correcting my homepage and it made no difference at all.
just something to add to your site to make it more colorful incase u run a site on a dull subject, other than that i dont think it serves any purpose
Personally, I think should matter when it comes to Search Engines even though it doesn't. A badly coded website causes all kinds of compatability problems.
Its to indicate the standard of compliant code used within a site/web page. Validation can be found here: http://validator.w3.org/ Having valid code obviously makes your code more concise and that fraction faster loading but also potentially means your site will display better over various browsers. Quite a lot of idiots add it to their sites even when their sites don't complie to the standard. Nope although obviously it shows that you can code good quality sites that are compliant - you could view it as an MOT for your website...
they have this one too - personally i think that search engines give some kind of favor to sites that adhere to quality standards
That one is used for valid css ie the style sheets that are used (usually for pure css layouts). Theres a similar validator for css as well...
it means the site is valid HTML, which yes is related to SEO in a way, as if your site isnt valid HTML then it will be harder for search engines when indexing your site.
If your code is valid - it is easy for crawlers to quickly crawl through the page. Broken code and crawler goes frenzy - not knowing where to go and surely won't crawl the page properly which can result in your pages being dropped off the SE indexes. The image has no relevance - it just tells your user that you have clean code.
If your website is webmaster related, then it might help having an image like that on it, otherwise it will look like not belonging to your project.
Okay i think there is a solution to this Yes or no for site validation: Official Google Web master Tips: http://www.google.com/support/webmasters/bin/answer.py?answer=35769#design Say "Check for broken links and correct HTML." Reading again, Check for correct HTML to me is saying, make sure its not full of tables bloating code. Correct Html coding I understand if you state your Doctype: !DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" It should actually meet those rules. And purely out of 5 years of building valid sites, i DO know lightweight XHTML is crawled easily and works in all browsers, even when they update. So Valid sites, definitely YES, YES.