From today's everything old is new again files, Blockchains and The Gray Lady.
While the most widely known usage of blockchains today is crypto-currency, all blockchains really are is an immutable, distributed, verifiable transaction log that lets you verify that not only is something what it says it is, it hasn't changed from the original.
Bitcoin has been around for almost 11 years, but what if I told you that almost 15 years earlier a company called Surety started one of (if not the) first public blockchains and used notices in the NYTs classified section as the public, distributed ledger for their hashes? Send them a document and they'd send you back the timestamped/hashed document and then they'd add it to their public hash which was (and still is) published in the NYTs every week.
While I'm pretty sure we don't need to publish the git sha's of our releases in the NYTs, wouldn't it be great if every bit of software we released (internally and externally) intrinsically had its git sha and creation date immutably embedded? You'd at least be able to get back to the code it was built from. Being able to build the identical (except for creation date) thing and then do testing on it would be great too, but hermetic, reproducible builds are a topic for a different day.