Checked my 6,921 bookmarks on Pinboard.in: 3,462 hit dead ends with 404s or expired domains, and many of the 3,459 left show fake content or parking pages. Only 21% from the last 2 years still work as expected. The lifespan of URLs is definitely shrinking.
Luckily some (~20%) are archived @internetarchive
What are we actually doing to avoid this?
