Back in November 2011 I wrote a little post about a problem I solved: IBM (formerly Lotus) Notes wasn't using the correct browser in Windows if Google Chrome was in the mix. The post peaked in 2013 yet is still the #1 thing people come to my site to view. In Japan we're on 2018 day 004. I already have 18 views on this one very old, very specific post. It started as a quick note so I wouldn't forget how to fix it.
I'm pleased people still find it useful while a bit surprised by the longevity.