hCard allows for data to be entered into address books, or used as Geo (see Wikipedia:WikiProject Microformats#Geo; Geo is a subset of hCard). It also allows birth dates (death date inclusion is pending) to be added to calendars as recurring events (including those for dead people, so that the anniversaries may be celebrated).
Adding adr to some Infoboxes, with a row for each address component, is difficult, because of the need to wrap class="adr" around several table rows, but not the whole table. In this case, the most useful address component should be marked up.
An extension (RFC 6474) for death-date, place-of-birth and place-of-death was published in December 2011.
It is proposed to use the following class names:
deathdate
birthplace
deathplace
The first of these will need to be baked into date calculation templates.
Note that the latter two may take a ADR microformat and/ or a geo microformat; (or a URI; not useful on Wikipedia) (as emitted by {{Coord}}).
Proposal: Where a microformat parser encounters a BIRTHPLACE or DEATHPLACE value which is text, but not formatted as an ADR, GEO or URI, treat it as vCard 4.0's ADR:LABEL.
8 May 1926 (age 80)<br style="display:none;" /><span style="display:none;">(<span class="bday">1926-05-08</span>)</span>
{{Start date}} & {{ISO date}} output the "bday" property, in YYYY-MM-DD, YYYY-MM & YYYY formats, for use in the hCards of organisations, venues and places.
{{Hcard-bday}} and {{Hcard-bday-place}} wrap the above in an hCard with a name inside a <span class="fn">.
{{death date and age}}, such as {{death date and age|1974|11|25|1948|6|19}}
To be modified as above, pending addition of death date field to hCard