In what year was the Linux kernel first released (and the first website put online)?

1991 → tub · bat.

In 1991 a Finnish student, Linus Torvalds, posted to a Usenet group that he was writing "just a hobby, won't be big and professional" — a free operating-system kernel he later named Linux. Combined with the GNU project's tools and released under the open-source GPL licence in 1992, it grew into the software that today runs most of the world's web servers, all Android phones, and nearly every supercomputer. The same year, Tim Berners-Lee put the world's first website (info.cern.ch) online, so 1991 quietly seeded two revolutions at once. Peg 19 · 91 → tub · bat: a bat hanging over a bath tub.