vCard and vEvent microdata in HTML5

I'm planning to assess the implications of the following sections of the
WHATWG HTML5 Microdata specification on our current specs:

http://www.whatwg.org/specs/web-apps/current-work/multipage/links.html#vcard

http://www.whatwg.org/specs/web-apps/current-work/multipage/links.html#vevent

This specification describes the way in which contact and calendar event
information can be marked up in a standard HTML page. Such markup should be
applicable for use in the download and save model we've recently added to
the Contacts and Calendar API specs:

http://dev.w3.org/2009/dap/contacts/#adding-and-updating-contacts

http://dev.w3.org/2009/dap/calendar/#adding-and-updating-calendar-events

This seems a good way to display contact and calendar event information to
users. With the aid of a Javascript library to convert these values in to
valid vCard and iCalendar objects (built according to the detailed
algorithms included in the WHATWG spec) the information can be downloaded
and saved to a user's address book or calendar according to the current
provisions in the DAP specs.

Perhaps an example, section or a couple of sentences are need to explain how
this microdata fits in to the Device API specs.

- Rich