Looks like a tactic to confuse search indexers.
When you watch ebot, its behavior becomes somewhat obvious. For whatever reason, its operators had the day off last night, and people complained the bread was moving extremely slowly. Ebot tends to aim for a specific rate of posts.
It has been, over the past few days, ripping book quotes and index search terms from the internet in what I can only imagine is a strategy to confound search algos that are, or are expected to be deployed against the CONTENT of the 8ch board. Since everything is archived and can be searched and indexed later, it would be a wise long-term strategy to confuse and frustrate search routines.
The seemingly random linking to other posts may also be a part of this.
I do not know what ends ebot has. People often assume that board fuckery means opfor, but at the same time, a lot of people come here to post things from all walks of life, some of which may potentially jeopardize key people. Loose lips sink ships, yet that is also the spirit of the board, that we must be able to speak about things.
As such, ebot makes for an interesting compromise between the two, helping to control board flow and confuse algos meant to defeat automated attempts to identify who is here, who has spoken about certain subjects, etc. I have no idea if it is all that effective or who deployed it (well, I have some guesses…) - but I can infer the purpose.