I've run sites that I've developed through various online SEO checkers over the years and some of them have checked me for my text to html ratio. I remember reading about this once or twice as well. I have to ask if there is any definitive proof of SEO penalties by, say, Google, when you have done your due diligence with alt/title attributes, schema.org, Facebook's Open Graph, etc, or when you are forced into one of those "div within a div within a div" designs where you end up with a LOT of code?
UPDATE I guess I wasn't clear enough in my question. I understand fully that your page should be useful and meaningful to your end user and not Google. When you have marked up your code so that your page has semantic meaning to Google(as you should!), your code ratio just keeps getting bigger and bigger. My question was if there is definitive proof that Google penalizes your page if the code outweighs the content by a certain percentage. Is this true or some sort of SEO urban legend?