We should make use of the HTML 5 <time> tag. W3C recommendation and WhatWG living standard.
Presently, the HTML emitted is something of the following sort:
<div class="wikibase-snakview-value wikibase-snakview-variation-valuesnak">13 November 2007</div>
It should probably be something like:
<div class="wikibase-snakview-value wikibase-snakview-variation-valuesnak"><time datetime="2007-11-13">13 November 2007</time></div>
Take into account dates and times in the W3C specification.