World of Warcraft might not have invented the wheel, but it certainly made it popular—and 20 years on, the MMO titan has fundamentally changed gaming's DNA

World of Warcraft's turning 20 years old soon, which means it's just one year away from being able to drink in the US, and two years into getting sloshed at the student union in the UK. Unlike me at that age, however, it's actually accomplished a ton. It was the first MMO to really achieve mainstream success and stay rooted there—becoming an engine of popular culture, rather than an occult activity practised in the shadows.

One thing I think it's easy to take for granted is how many mechanics WoW popularised that have...