A massive repository of 100M+ course-specific documents, now a part of the Learneo group. In 2025, it integrated QuillBot for AI writing and Symbolab for step-by-step math. While its library of previous exams and lecture notes is unrivaled, its high monthly cost and 'unlock' system are often criticized by students on a budget.

The dominant flashcard platform, now powered by generative AI. Key 2025 features include 'Magic Notes' (turning lecture notes into study sets instantly) and 'Q-Chat' (a Socratic AI tutor). While its library of 700M+ sets is unmatched, the strict paywalling of legacy study modes and aggressive annual billing have sparked a search for free, AI-native alternatives.