People form dynamic groups focused on topics that emerge serendipitously during everyday life. They can be long-lived or of short duration. Examples include people interested in buying the same product, those with similar expertise, those in the same location, or any collection of such attributes. We call this the Human Discovery Protocol (HDP). Similar to how computers follow well-established protocols like DNS in order to find other computers that carry desired information, HDP presents an open protocol for people to announce bits of information about themselves, and have them aggregated and returned back in the form of a group of people that match against the user�s specified criteria. We are experimenting with a web-based implementation (brin.gy) that allows users to join and communicate with groups of people based on their location, profile information, and items they may want to buy or sell.