404
38% of webpages that existed in 2013 are no longer accessible a decade later
(www.pewresearch.org)
This is a most excellent place for technology news and articles.
It would be interesting to know how many of these references don't exist anymore and how many have just moved. Web has come a very long way since 2013 and I bet that websites hosting the references have undergone several iterations altering the URLs in some way.
That, in and of itself, is also a problem! First of all, because such pages often fail to return a
HTTP 301 moved permanently
response, and second (but perhaps even more importantly) the reason they move is because the site transitioned from using static, human-readable URLs to some kind of unstable CMS-managed non-descriptive gibberish that breaks caching and linking. It's an intentional siloing and hoarding of content.And how many are the site completely re-jigging their CMS with no forwarding set up.