[unboggling]

But seriously, on the general issue raised in the first post above, I don't worry about it.

Anyone with serious resources -- such as a government agency -- can know or learn pretty much everything about me. The tracking and profiling doesn't bother me, because I filter out as much advertising as possible anyway. I'm not political. I'm not a threat. So why would anyone waste time messing with little old me?

On one hand I find it mildly annoying that some of what I read might be tracked. For example, a few weeks ago I was reading a novel in which a character murdered someone with an esoteric poison I'd never heard of. I looked it up on Wikipedia, aware that it might become known in the future that I'd looked up that poison on Wikipedia that day. So I'd better not kill anybody using that poison, or perspicacious investigators might unearth that suspicious research. It was a passing thought and mildly annoying. But since I don't intend to ever poison anybody, that remains minor annoyance.

On the other hand, I understand why the security agencies want as much raw data as they can get. It's a cold, cruel world and there are lots of crazy or malevolent people in it. I feel a little safer knowing people are watching for internal or external security threats.

So, the mild annoyance balances the mild sense of safety and I don't worry about it. Because I'm not a criminal, terrorist, or spy.

Meanwhile, I use calibre to manage the books I read.

Reiterating what MelBr mentioned above: They don't need backdoors into calibre or even operating systems. The NSA (for example) is reputed to have supercomputers, decryption experts, network experts, and raw internet packets.