The most popular microphone used by YouTubers is the Blue Yeti USB Microphone. It's a great choice for both professional and amateur content creators, as it offers excellent sound quality and a wide range of features. The mic has four different pickup patterns to choose from, allowing you to tailor your recordings to any situation. Additionally, it has an adjustable gain control and zero-latency headphone monitoring for added convenience. With its plug-and-play design, the Blue Yeti is easy to set up and use right out of the box - making it an ideal choice for anyone looking for a reliable microphone at an affordable price point.