Let me just explain the demo that got me excited about Surf, a new browser coming from a startup called Deta. Max Eusterbrock, one of Deta’s cofounders, shared his screen with me over Zoom and asked me to pick a YouTube video. I told him to search for Cleo Abram’s latest, about digging through the center of the Earth. “Do you have a question for the video?” Eusterbrock asked. I took a second to figure out what he meant, then remembered Abram had mentioned something about exactly how…