Why do YouTubers clap at the start of videos?

It's about synchronisation, right? Well, not exactly... 🟥 MORE FROM TOM: https://www.tomscott.com/ (you can find contact details and social links there too) 📰 WEEKLY NEWSLETTER with good stuff from the rest of the internet: https://www.tomscott.com/newsletter/ ❓ LATERAL, free weekly podcast: https://lateralcast.com/ https://youtube.com/lateralcast/ ➕ TOM SCOTT PLUS: https://youtube.com/tomscottplus 👥 THE TECHNICAL DIFFICULTIES: https://youtube.com/techdif