The article explains it in the first few paragraphs. Here is paragraph 2 and most of paragraph 3:

Chegg should be familiar to most people who have been to college in recent years. It started out in the 2000s renting out textbooks and later expanded into online study guides, and eventually into a platform with pre-written answers to common homework questions.

Unfortunately, the launch of ChatGPT all but annihilated Chegg’s business model. The company for years paid thousands of contractors to write answers to questions across every major subject, which is quite a labor intensive process—and there’s no guarantee they will even have the answer to your question.