Powerline.io is a browser-based .io game that released in 2017. These types of games generally have strong early popularity but decline after a few years, although a handful maintain a steady niche audience. As of 2024, retention is likely modest but stable, with thousands of daily players, similar to other .io games like Slither.io. The game runs on lightweight multiplayer lobbies, not a persistent world, so it's not an MMO.