Monday marks the 20th anniversary of when the first text message was sent. Neil Papworth used a PC to send an early Christmas greeting to the cellphone of Richard Jarvis of Vodafone. Since then there have been trillions of texts shuttled around the globe, each delivering their messages in 160 characters or less. But, as the text message turns 20, the key question is whether the venerable short message service (SMS) is already over the hill. After all, it has all kinds of rivals. Read the full story at All Things D.