Pokémon GO has already become a massive hit in the short time since its release. The augmented reality game for Android and iOS allows players to capture Pokémon from real-world locations using their smartphone's camera. Unfortunately, the game is not yet available in all regions. This is likely a precaution against having a volume of players that exceeds what the game's servers are capable of handling. Still, that hasn't stopped players in regions where the game is unavailable, such as South Korea, from downloading and sideloading pirated copies of the APK onto their devices.
Nintendo, however, has begun taking measures to keep this from happening. Aside from creating a demand for the game that may overwhelm the servers, sideloading apps can present security risks, particularly if the apps in question have been modified in some way. In an effort to keep players from sideloading the app onto their devices, Nintendo has issued takedown requests to some of the websites hosting unauthorized versions of the game. While this may eliminate some copies of the game, it is unlikely to rid the internet of them entirely, as those who have already download pirated copies can simply post them to a different website. In order to reduce these occurrences as much as possible, the game would likely need to incorporate some system that would check whether it had been obtained from a legitimate source.
While the game is currently only officially available in the United States, Australia, New Zealand, Germany and the UK, 6.8% of all Android devices in Canada and the Netherlands have already installed it. On The Pirate Bay, one of the most popular torrenting websites, Pokémon GO is the most shared game by a large margin. APKmirror.com, a popular website that hosts APK downloads for Android apps, has seen their traffic increase by millions of users a day since the game's release. While the amazing popularity of the game speaks highly of its entertainment value, Nintendo clearly wants players to go through the proper channels to install it on their devices, and there is no way to know what other methods they will put into place to discourage players from installing pirated copies. For those who live in regions where the game is not yet available, the safest approach is probably to be patient and wait for it to arrive in your country.