In the time before the apocalypse, it turned out that Charles Snippy belonged to the 1% who weren't able to connect with the ANNET. He had to take therapy sessions that were supposed to study and maybe solve the problem. The therapist suggested that Snippy should regularly write diary entries. Even though Snippy suspected the therapist being nothing more than a computer program, he actually decided to follow 'her' advice.
Snippy's journal is actually a chip in a titanium shell that was embedded into one of his teeth. While he can record diary entries with it, he has no possibility to replay them. It is not even sure whether the chip is still operating, since Snippy got hit by a beam from the orbital ion cannon.
Snippy creates new entries regularly: