It seems like any other sites or app that gives you an insight on how to dominate the Pokemon Go games are not allowed to exist at all. Niantics have been shutting down third party apps and sites that could track the locations of Pokemon but it looks like Niantics is not done yet.
The site PokeAdsivor which was used by fans to gather data was taken down. The site, which contains features like trainers statistics, leaderboards, and an IV calculator which players can use to calculate the full potential of their Pokemon so that they don’t have to waste any Stardust and candy on them if they have no potential of over becoming great.
PokeAdvisor is now attempting to get the website reconnected on Reddit but we don’t know if they will ever succeed. If Pokevisio is the example, this is probably the end of PokeAdvisor.