If you thought that the "I was here" style graffiti is a modern-day phenomenon confined to the backs of bathroom stalls, think again! New technologies are unearthing graffiti scratched on ancient sites like never before, giving voice to everyday people of the ancient world — from enslaved individuals to bored soldiers who etched their names onto walls. The ancient graffiti research epicenter, so to speak, is the once-bustling city of Pompeii , which was buried in the eruption of Mount Vesuvius in AD 79. The eruption left buildings exquisitely preserved under meters of ash. Since excavations started in the 18th century, archeologists have mainly kept busy uncovering colorful paintings, frescos and mosaics in the homes of the city's elites.…