I ran a fairly niche website for a while, starting around 2006. It was pretty terribly designed (eg I learned sql and javascript from working on this project),

I ran a fairly niche website for a while, starting around 2006. It was pretty terribly designed (eg I learned sql and javascript from working on this project), used the whole kitchen sink of css/html/javascript circa 2006, and still, it never stopped working. The site is actually older than that -- it started around 2004 I think. So even poorly written web apps have longevity sometimes, even when you don't intentionally design for logevity. So, the oldest code I wrote that's still running is a bunch of web stuff.