[a3n]

There are at least two ways of hiding information here: how much of the text to send in one go, and the time the text is sent. You could vary both to signal information about something, even though the text doesn't lead directly to any message.

A green flare is shot into the air at 11pm. Or, two green flares are shot. That's a pre-agreed signal that something did happen, something will happen or something should happen.

A paragraph is sent on August 2nd. Or, two paragraphs ...

[Houshalter]

Yes but that's a very limited amount of information, maybe only a few bits. Seems like a pretty inefficient way of hiding such a small message.

[tomjen3]

If you send between 1 and 4 paragraphs from one of four different works, a day, it doesn't take that long to send the 2048 bytes necessary to create a public key, or the 512 necessary to give the hash of one.