This post copies word-for-word (without attribution or a link; shame on you) an announcement from Fordham referencing The Supplemental-Curriculum Bazaar: Is What's Online Any Good? (66 page PDF) by Morgan Polikoff and Jennifer Dean. The reviewers "examined over three hundred of the most downloaded materials found on three of the most popular supplemental websites: Teachers Pay Teachers, ReadWriteThink, and Share My Lesson." According to the study "these sobering findings reveal a major mismatch between what content experts think educators should (and shouldn’t) use in classrooms and what teachers, hungry for instructional resources, are choosing to download." But the problem may lie with what the experts think should be used, or more likely, with the criteria used in the evaluation.