Natural colors only for now. Brighter shirts can be bought later at the boutique.
It shows as a banner across every player's screen for a few seconds, and stays in chat.
Every area has one dig spot. Every 6 hours they all move somewhere new, dug or not. NEW SPOTS EVERYWHERE puts a fresh one in every area now and starts the 6 hours again. SPOT BESIDE ME adds an extra one on the grass next to you (also /digspot).