Telemetry, or tele-metering, is automated remote measurement and data collection. It’s used in all kinds of industries, from tracking spacecraft, tracking wildlife, medical monitoring, law enforcement, and so on. The electrical meter attached to my house, for example, automatically sends readings to the utility company, which has eliminated the need for human meter readers. I especially like to think of telemetry in the context of spacecraft, where it is the way in which mission controllers monitor the health and operation of a very expensive piece of hardware that is completely unreachable any other way.
Putting an app into the global market is, in many ways, similar to launching a spacecraft: without telemetry, you’re flying blind. Your app represents a significant investment, and once it gets out to more than a handful of customers the main issue is not so much distance, but scale. And what you need is a way to both collect the data and then condense it into useful analytics, or reports that human beings can read to make decisions.