An anonymous reader quotes a report from TechCrunch: WhatsApp this week started rolling out username reservations ahead of the broader launch planned later this year. The feature -- which lets people find and message each other by handle instead of phone number -- is already raising impersonation concerns, drawing scrutiny from security experts and regulators in India, the app's largest market, with more than 500 million users. The rollout marks a shift in how people identify one another on WhatsApp. Instead of relying on phone numbers as the primary identifier, users will increasingly interact through platform-managed usernames, a change that Meta says improves privacy but that critics argu...