Sentiment analysis is the process of reading the emotional tone of comments, replies, reviews, chat messages, and off-platform mentions to gauge how an audience actually feels about a video, creator, or brand. On YouTube, sentiment analysis typically combines comment scraping, keyword scoring, and increasingly AI models that classify feedback as positive, neutral, negative, or mixed. Creators use it to spot which video beats sparked confusion, which topics fatigued the audience, and which uploads earned genuine enthusiasm, then feed those findings back into the content plan.