#YUIConf #HTML5 follow-up: w3.org, validator.nu are different. Use w3.org/html/check for latest HTML5 validation. Examples (as of 2010-331 18:32 PST) of where w3.org/html/check is more up to date: 1. <s> element recently added back to HTML5, and 2. datetime attribute of <ins> and <del> now permits date-only syntax. E.g. compare: http://www.w3.org/html/check?doc=http%3A%2F%2Ftantek.com%2F2010%2F309%2Fb1%2Fembed-html5-videojs-open-video-conference-nyc and http://validator.nu/?doc=http%3A%2F%2Ftantek.com%2F2010%2F309%2Fb1%2Fembed-html5-videojs-open-video-conference-nyc