Its been almost a week since pokemon tracking has vanished from Pokemon Go. The app's user amount most certainly peaked as most are finding the game to be unplayable without in-game tracking, and the shutdown of many popular Third-Party pokemon tracking apps (at the request of Niantic, the game's creator) has left users in the dark. All of this without a single sliver of communication from Niantic, and like the ALS Ice bucket challenge, we could be looking at another summer fad.
Update Niantic just sent out this press release