[akomtu]

One app gets your IP address and sells it to data brokers in real time. Another app buys this data and correlates it with IP addresses it knows. In practice, there are hundreds of data points as smartphones are all about data collection.

[surveilled]

Yes part of it works as you’ve suggested, the ID part.

However, there’s more at play. Somehow there is access to data about whom I contact (again only via iMessage) and the contents of messages (only via iMessage). It’s not an imagined correlation, some of the data shown on the app could only come from recent iMessages.