Amateur Pokemon Go enthusiasts have innovated a wide variety of services and apps designed to help players easily locate Pokemon. Apps like PokeVision are great for Pokemon Go players frustrated with the infamous "three step bug" that prevents players from tracking Pokemon properly. However, while PokeVision may be popular with the fans, Niantic Labs, the developer of Pokemon Go, isn't as happy with new development.
In an interview with Forbes, Niantic Labs CEO John Hanke spoke about the various apps that show where Pokemon are spawning in the game. "Yeah, I don’t really like that. Not a fan," Hanke told the website. "We have priorities right now but they might find in the future that those things may not work. People are only hurting themselves because it takes some fun out of the game. People are hacking around trying to take data out of our system and that’s against our terms of service."
However, apps like PokeVision are more of a tool for Pokemon Go players, albeit one that does access Pokemon Go's servers in a way Niantic didn't intend. Niantic could probably figure out how to shut down these apps pretty easily, since they use a normal log in as opposed to some sort of "back door" into the server.
Since Hanke also mentioned they had "other priorities" before shutting down these apps, it's possible Niantic plans to fix the three step bug before taking action against PokeVision and other apps. After all, these apps were largely created as a response to fans unhappy about Niantic shutting down Pokemon Go's tracking function, allegedly in an attempt to help improve server performance.
There's been at least one (unconfirmed) report that The Pokemon Company has begun sending out cease and desist letters to users who create bots that automatically catch Pokemon, so it looks like Niantic and The Pokemon Company may already be taking action against people outright cheating the system.