In fps games, this strategy is used to avoid snipers by making the player go in a circle-like motion.
Teammate: "They got a sniper on the enemy team, better be careful going through his sightline."
Player: *goes through sightline* WASDWASDASDWASDAWSDWASDWASDAWSDWASDWASDWASDWASDWASDAWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW.
you: imatype wasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwadwasdwasdwasdwasdwasdwaswasdwasdwasdwasdwasd and see what happens
But in our case "wasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasd" is when either a developer or gamer is bored out of their fucking minds and they decide to type in some random shit to see what would come up. Or a developer would use it to test something in their code.
alert("wasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasd");
Or
Googlesearch: wasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasdwasd