[Rebelgecko]

Oh cool, I haven't read Fall but it's similar in Anathem

The reticulum (aka internet) is filled with software generated crap. Initially most of it is blatant and easy to filter out, like an over the top "but cheap v14gra" spam email.

Eventually the companies that make the crap filtration software get into an arms race with each other, they realize if they can generate their own crap that their competitors don't detect, it'll give them a competitive advantage. The reticulum becomes filled with "high quality" crap, eg text that's ALMOST correct but wrong in subtle ways. Imagine a wiki article about pi where everything is correct except the 9th digit, or an op-ed with slightly flawed logic.

Eventually crap goes beyond text, and the reticulum starts to see deepfaked images and videos that parallel news articles. One of the jobs of the ITA is to try and find the signal in all the noise.