The nature of 4chan makes it more difficult to distinguish from just normal posting. There's not any kind of paper trail to look at and potentially ID the posters.

It's also somewhat expected on the site from a cultural standpoint? Having a recognizable posting pattern gives flavor to a system that is otherwise composed of completely interchangeable posters. Like /v/ has one guy that constantly makes threads that are designed to devolve as quickly as possible into posting images of anthropomorphic lizards. It's not much of a nuisance so much as it makes the place feel comprised of genuine people.