Text - Introducing HTML5 - page 65

don't know what public-key cryptography is, take a look at
http://en.wikipedia.org/wiki/Public_key .
And if you're still lost, you don't actually need this element!
<progress>, <meter>
<progress> is used to represent a “progress meter,” to indicate
the completion of a task—downloading a fi le, for example.
<meter> “represents a scalar measurement within a known range,
or a fractional value; for example disk usage, the relevance of
a query result, or the fraction of a voting population to have
selected a particular candidate.”
<menu>, <command>
These are exciting elements that allow you to defi ne toolbars or
context menus for your application, with icons and associated
commands that execute scripts when activated. They're cooler
than a bucket full of Lou Reeds. However, no browser yet sup-
ports them, so we don't discuss them further.
microdata
microdata is a method of marking up elements with additional
machine-readable data, so that crawlers, search engines, or
browsers can extract information from the page. It's similar to
RDFa (a W3C standard) and microformats (a popular set of con-
ventions), and is already indexed by the Google search engine if
used in markup. However, no browser supports its associated API.
<style scoped>
The scoped attribute on a style element tells the browser
to apply the styles to the element that the <style scoped>
element is in, and its children. This allows for highly localised
styling right inside your HTML, an <article> that contains a
scoped style block can be syndicated and retain its special
styles, for instance.
However, no browser supports it yet.