Predatory Open Access Publishing is the name given to a problem that has recently developed in academic publishing. Some journals now allow authors to pay fees that cover publication costs. These articles can be made freely available to everyone on the internet. This is known as "Open Access" publishing.
There are many legitimate Open Access publishers and this process is well established. The problem is that there are also many "predatory" publishers that will charge authors these publication fees and not provide any of the services that legitimate publishers provide, like editing and peer review management. Predatory publishers primarily want to collect the publication fees. Once predatory publishers have collected an author's money and article manuscript, little can be done to retrieve manuscripts and author fees from these non-scholarly publishers.