Kezia Happy found Brainly:

• Significantly builds student knowledge“For problems, Brainly allows access to both answers as well as detailed explanations.”
• Significantly increases student collaboration“Brainly is student-supported. Students answer questions and receive points. With these points, students can ask their own questions. There are incentives to answer correctly as well as moderators (often students as well) that ensure answer quality.”
• Moderately reduces teacher workload“Students can ask about questions or concepts they are struggling with. This helps to lessen the load of educators.”