NotebookLM.

Google's AI learning tool. Each notebook is a subject you want to learn about. You upload your source material (a course, a stack of videos, your own docs) and now it's a mini brain that's an expert on that topic.

The difference from just asking ChatGPT is that it only knows what you fed it, so its answers stay grounded in your sources instead of wandering off. You can chat with it like a tutor who's read your material.

Then it spins that same material into other formats: quizzes, flashcards, a podcast you can listen to, mind maps, even explainer videos. One upload becomes a dozen ways to learn the thing. Good for getting up to speed on a dense topic fast, or turning your own content into something you can study.