Most people don't know what HTML is, yet they can use web browsers. Not knowing HTML 5 will not prevent them from using HTML 5 -- and HTML 5 is covered by the f

Most people don't know what HTML is, yet they can use web browsers. Not knowing HTML 5 will not prevent them from using HTML 5 -- and HTML 5 is covered by the first half of that list. The mailto extensions don't have to be -- they could as easily be built into the browser (and should be by now). Web applications can already be online/offline hybrids (Google Gears already provides the functionality, HTML 5 adds it as well).