Open-access journals provide their content to readers for free, often funding their operations by charging authors a fee for publication. The average fee is under $500, but a few journals charge much more than that--sometimes $1,000 or more.
Most of those journals are reputable and peer-reviewed. But many are not and exist solely to make money--which means they'll publish virtually anything someone submits. A recent sting has now exposed the dubious practices of several of those journals, which invited a fake scholar to join their editorial boards. The results of the sting are published in the latest issue of Nature.