Pokémon Go is unquestionably this season's hit game. But whether it has any staying power is a very open question, and early signs suggest it's already trailing off.

Bloomberg has published some charts by Axiom Capital Management that show daily users and engagement dropping. One chart, using data from analytics firm Apptopia, shows Pokémon Go peaking at around 45 million users in mid-July, during the week or so following its launch. It then begins a decline to somewhere above 30 million daily users last week.

That's not great news for the game's creator, Niantic, though it isn't necessarily terrible news either. Apps and services typically measure their usage in monthly users, not daily users, because it's so much harder to get people hooked enough that they come back day after day. Niantic was never going to be able to keep the Pokémon phenomenon as strong as it was around launch, but it's possible it'll be able to keep its numbers more stable on a month by month basis.

We're just over a month out, so it's too soon to know exactly how Pokémon Go is faring in the longer term. But there are still signs that it's doing well: it's the number one free game in the Google Play store (and number four free app overall), and it's the number two free game in Apple's App Store (and the 11th most popular free app overall). The game is also yet to launch in many parts of the world, where it'll pick up new users and could start to grow again. But the early data, at least, suggests it isn't likely to maintain its status as an ubiquitous, always-open hit.

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