I'm relieved. It never occurred to me that horse_ebooks was a spam bot until I started reading other people stating with certainty that it is a spambot. It always struck me as a human posing as a spambot because it was too clever and poetic.
It also surprises me that so many people think we're more likely to encounter a legitimately clever spam bot than a clever human impersonating a spambot.
I only ever saw retweeted or starred tweets from it (as I quit direct twitter a while back, deciding instead to view it only through Stellar).
I had assumed that what I saw was a tiny proportion of tweets — those that were funny and/or poetic. If I'd know they all were than I'm sure I would have never thought it was a bot.
It also surprises me that so many people think we're more likely to encounter a legitimately clever spam bot than a clever human impersonating a spambot.