Elon Musk’s X to Brands: Advertise With Us or We’ll Sue

X launched a strong-arm campaign against advertisers to revive its ad-sales business. WSJ advertising editor Suzanne Vranica tells us about the unusual tactic. Plus, the "unsubscribe" button at the bottom of marketing emails may be an easy way to opt out. But writer Heidi Mitchell will tell you why you shouldn’t be so quick to click. Sign up for the WSJ's free Technology newsletter. Learn more about your ad choices. Visit megaphone.fm/adchoices