Such a security apparatus would collect any and all information it can get its hands on, and then use it whenever it needs it. For instance to protect the state, to protect itself, to influence and manipulate situations to its advantage and to the advantage of those in power, to destroy opponents and of course for fun and profit.

A contemporary Stasi would control Facebook and use all algorithms and all available data sources to figure out who the persons of interest are. Even assuming that the StasiBook app wouldn't auto-upload all pictures and microphone data (why would an upstanding citizen turn off their mic?), they could still correlate many invisible patterns.

So all in all, I think they'd be the biggest fans.