Gregory held back from joining until he met some OSM guys in the UK in 2006. You may have seen him shout "Maps" on the stage, but he really enjoys chatting to people in the breaks. If it's your first time or you've got every SotM t-shirt that exists, do find him and say hello.
We've learnt about many projects and clever systems that run OpenStreetMap possible, but it's the individuals that are most valuable in what we do. Settle down in your seats as Gregory introduces you to a selection of OSMers and informally chats to them about their involvement. When, how, and why did they join OSM? What do they do in the project? Has that changed? What's their favourite map tag? All these questions and more will potentially be asked.