My first instinct was it might be a function on the server that calculcates the years passed dynamically from today. A quick look with Wayback Machine showed this number 22 is hardcored into the webpage. So the question is, what that means. Obviously it cannot be 22 years ago from the time of writing the article. Valve didn't exist in 1987. Quake came out in 1996 and then someone did the Team Fortress mod for that game. Which Valve created the standalone game Team Fortress Classic a few years later. And Team Fortress 2 came out 2007 (it wasn't Free to Play back then).
Or do he refer to some ideas written on paper, but was not able to create a game with it back in the 80s? Or it's just a typo and I over analyze this. I need help. Medic!