[im] Making <time> safe for historians

[János Sugár]

The HTML 5 spec introduces the <time> element to mark up a date or 
time. Although I support the inclusion of these semantics in HTML, I 
believe that the current specification of the <time> element is vague 
because it avoids the question whether the element is safe for 
historians. Right now it hurts historical research more than it 
helps. In this entry I'll explain why.

Although I will concentrate on the HTML5 syntax here, what I have to 
say also applies to the microformats datetime design pattern. The 
Microformats site adds one important detail to the discussion that 
the HTML5 spec overlooks: the point of having a <time> element (or a 
datetime design pattern) at all:

Use the datetime-design-pattern to make datetimes that are human 
readable also formally machine readable.

Who needs machine readable dates? As far as I can see there are two 
target audiences for this operation. The first is obviously social 
applications that have to work with dates, and where it can be useful 
to compare dates of two different events. An app must be able to see 
if two events fall on the same day and warn you if they do.

However, as a target audience social applications are immediately 
followed by historians (or historical, chronological applications). 
After all, historians are (dare I say it?) historically the most 
prolific users of dates, until they were upstaged by social 
applications.

This raises the question whether the <time> element should be 
tailored for historical use at all. When I started writing this entry 
I was convinced that it should.
/.../
https://www.quirksmode.org/blog/archives/2009/04/making_time_saf.html