@embolalia A followbot simply follows any account they see a post from. That causes the followed account's tweets to be federated to the followbot's instance even if no humans are following them. Their supporters like them because they make the federated timeline richer; their haters dislike them because they make things noisier.
@Nentuaby @embolalia noisier and inorganic. inorganic being not "letting federation work the way it is meant"