[nirvana]

That Apple makes the iPhone and iPad is not a secret. The article you link to is talking about stats that apps are reporting over the internet... the apps have to know what kind of device they are running on, and have to be able to handle differences between the devices (eg: the screen difference between the iPhone 4S and iPhone 5).

No real information is released with these hardware model numbers that's not already reasonably known.

The only exception is for devices that people might think are end of life, or unlikely to get a refresh soon.

For instance, the Mac Pro may start showing up in logs, and that would be news, because it is so rarely updated... or it would be news if Tim Cook hadn't said that they planned to release an update (in 2013? not sure when he said it would be.)

So, knowing that iOS 7 (8, 9, etc.) are under development doesn't give away any of the secrets-- eg: what the special features of those OSes will be.

[bgarbiak]

Well, you can get some real secrets by combining user agents with other data. For example: screen resolution.