This note contains spoilers for the book.

Privately run mail packets are apparently viable, even though there is FTL visual contact from the ends of the universe back to Earth. They carry high-volume high-value data. There's no discussion of encryption issues; not clear if they're considered more secure from theft.

But it gives the excuse to play with AIs loose on the ship (with several rabidly anti-AI people on board; when AIs wake up they tend to destroy the infrastructure of the plane they're on).

And the mysterious Fools' Guild appears to be made up of embodied AIs (and nobody else knows how to do that), and their main work is to prevent the disasters and rescue the AIs at the same time.

This seems to be two novels strung together; I'm just about half way through, and they've made their escape from the planet they accidentally unleased an AI onto, with the AI intact. So presumably there's another novel's worth of plot coming. Hmmm; I guess the opening scene hasn't tied into anything else yet, either.

Well, okay; so there are two groups of AIs, there's a breakaway faction as well as the Fool's Guild. And they accidentally collaborate to nearly start a war of extinction with the humans, with nobody wanting that, but they manage not to, and it all rolls up very quickly into a decent outcome, even though one of the main characters loses her husband. The end.

I don't believe in their ability to plant any accidental AI into a human brain; I think they'd be too different, and probably none of them would work, but certainly all wouldn't work. In fact I don't believe in the whole AI concept they have, and besides what they call AIs aren't real AIs, they aren't awake; that's a special extra step that happens by magic (and the Freers believe it involves trapping a human soul).