What are they?
Predatory journals and publishers
Open Access predatory journals and publishers require the payment of article processing charges (APCs) for services that they claim to provide - however, they often don't provide them at all, or very superficially.
These claimed services include archiving and indexing policies, editorial review, copy-editing, formatting, and the organisation of the peer review process.
Some predatory journals and publishers sometimes collect APCs without even publishing anything at all!
How is this possible?
Predatory publishers and journals hijack the "author-pays" Open Access model which is common in scholarly publishing. This model allows readers to have free and open access to the contents of research where publishing fees are paid by authors, their institutions, or funders.
However, the "author-pays" model is not the most common in Open Access publishing. More than 70% of journals included in DOAJ ( the Directory of Open Access Journals) do not require the payment of APCs.