Jeffrey Beall is an academic librarian at the Auraria Library at University of Colorado Denver located in Denver, Colorado. He got tenure in 2012 and became an associate professor. For a number of years, he has maintained and curated a blacklist of allegedly (he calls it “potential, possible, or probable”) predatory open access publishers.
Predatory journals can engage in a large number of suspicious activities, such as deceptive journal name, sending massive spam requests to authors and reviewers, falsely claiming to have a higher credibility than they have based on common journal metrics, publish a lot of fake content, do not engage in peer review despite claiming to etc. It turns out that this list is not the only thing that is gone. The lists of predatory as bellow:
List of questionable, scholarly open-access publishers.
A counterfeit website that pretends to be the website of a legitimate scholarly journal. The legitimate versions of the journals are only published in print form and they may not have websites.