Hello everyone,
My apologies if this has been discussed before, but I just noticed that Wikipedia pages carry a doctype declaration of <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
Since this does not include the URL to a full DTD, the curse of doctype sniffing sees most browsers render the page in "Quirks" or "Bugwards compatible" mode rather than "strict" mode. In the interests of making wikipedia accessible, I think it would be better to force strict mode - then editors would be more likely to notice markup errors which affect the rendering on browsers which do not correct for bad markup.