Bearing in mind that the title and meta description are very important, do you think any of those sites are affected? I do.
Nah, the general consensus round' here is that it doesn't matter. As long as the visitor can see and use your website, that is all that matters. There is no need to write valid code. None, whatsoever. Google is a fine example of that. If they can do it, why can't I?
I'm off to break a few pages just so I can feel good about myself and get the "new me" started.