New Delhi, Aug. 1 -- It's 6.30pm, and Isha Kumar, 25, a marketing professional, is standing in a packed compartment on the Delhi Metro. She slips in her earphones, opens WhatsApp, and hits play. Just like that, she's no longer on the crowded train; she's with her best friend, who describes the chill in the London air, the toppings she picked for her oatmeal, all accompanied by the sound of her footsteps, pacing her way to work. Her friend, away from Delhi for the first time, tells Kumar, "Your comforting voice, laced with the muffled rumble of the Metro, is my virtual hug from home."

This kind of intimate, asynchronous exchange has become second nature for many. In 2024, WhatsApp users around the world sent nearly 150 billion messages da...