[whatwg] Link rot is not dangerous

[Kristof Zelechovski]

Serving the RDFa vocabulary from the own domain is not always possible, e.g.
when a reader of a Web site is encouraged to post a comment to the page she
reads and her comment contains semantic annotations.

The probability of a URL becoming unavailable is much greater than that of
both mirrored drives wearing out at the same time.  (data mirroring does not
claim it protects from fire, water, high voltage, magnetic storms,
earthquakes and the like; it only protects you from natural wear.)  The
probability of ultimately losing data stored in one copy is 1; the
probability of a URL going down is close to 1.  So, RAID works in most
cases, CURIE URL do not (ultimately) work in most cases.

Disappearing CSS is not a problem for HTML because CSS does not affect the
meaning of the page.

Disappearing scripts are a problem for HTML but they are not a problem for
HTML *data*.  In other words, script-generated content is not guaranteed to
survive, and there is nothing we can do about that except for a warning.
Such content cannot be HTML-validated either.  In general, scripts are best
used (and intended) for behavior, not for creating content.

External SVG files do not describe existing content, they *are* (embedded)
content.  If a HTML file disappears, it becomes unreadable as well, but that
problem obviously cannot be solved from within HTML :-)

"HTML should be readable in 1000 years from now" was an attempt to visualize
the intention of persistence.  It should not be understood as "best before",
of course.

If the author chooses to create a redirect to a well-known vocabulary using
a dependent vocabulary stored at his own site in order to prevent link rot,
tools that recognize vocabulary URL without reading the corresponding
resources will be unable to recognize the author's intent, and for the tools
that do read the original vocabulary will still be unavailable, so this
method causes more problems than it solves.

Cheers,
Chris