Bury a time capsule in a schoolyard and dig it up 20 years later. The letters and photos inside may be faded but still readable. But if you put a URL on paper inside that capsule, would the link still work 20 years later? The answer is almost certainly no.
Research data on URL lifespans is shocking. A 2014 Harvard Law School study found about 49% of URLs cited in Supreme Court decisions were already broken. A New York Times investigation revealed about 72% of external links in their online articles broke within 10 years. For short URLs specifically, about 61% break within 2 years. Statistically, the probability of today's short URL surviving 10 years is very low.
The main cause is "Link Rot." Website redesigns, domain expirations, server shutdowns, and content deletions all kill URLs. Corporate websites are redesigned every 2-3 years on average, often changing URL structures. Digital preservation books are available on Amazon.
Efforts to deliver URLs to the future exist. Internet Archive's Wayback Machine, operating since 1996, holds 800+ billion page archives. Perma.cc, developed by Harvard Law School, provides permanent archives for URLs cited in academic and legal documents. Blockchain-based URL permanence using IPFS (InterPlanetary File System) is also being researched.
Ultimately, digital permanence depends on someone continuously bearing the cost of maintaining data. Paper letters in a time capsule remain readable after 20 years. But URLs disappear within years without someone maintaining them. The digital world is far more ephemeral than we think.