On (X) Android app review - Telegraph How often do you leave the house without an umbrella, even though you knew it was going to rain? On (X) is a new app that automatically follows rules and performs actions - so, for instance, it checks the forecast in order to remind you specifically: "Take an unmbrella." As yet, this Android app designed by Microsoft is not yet fully formed: its main audience for now is developers who can write the "recipes" that make it work. These are growing in number already, although they must still be created or adopted on the website and then pushed to your phone. There is plenty on the site to allow anyone to have a go at the necessary Javascript programming, although few are likely to take the plunge. A number of other apps do similar things, but none that I've come across has quite On (X) "s sophistication. It can, for instance, detect your speed of travel and act accordingly - put the music player on when you're running for instance. Obviously this use of GPS is not ideal for battery life, but that is hopefully a problem technology can solve in due course. Motorola's "Smart Actions" for instance offer many of the same actions, but of course this is only available for that one manufacturer's devices. Another example is "When my boyfriend texts me "where" reply automatically with my location" - encouraging the phone to know who is communicating with it, what they want and simply doing it automatically, using data from the real world, is a huge amount of progress compared to what even most smartphones currently do. This is not yet a pretty app, or a detailed one as yet. But it can already perform really useful tasks. Microsoft give examples such as "text my wife when I'm leaving the office." It won't be long before the Ideal Home Show dream of automatically communicating with other machines and heating up the oven as you leave work is a reality.