During YC startups have weekly office hours with their group partners. As a part of Startup School we invited attendees to volunteer for office hours on stage. Kevin and Qasar chose three marketplace companies for this round of office hours.

Traveling Spoon - https://www.travelingspoon.com/
Steph Lawrence and Aashi Vel
Traveling Spoon is a food and travel marketplace.

HumanSurge - http://www.humansurge.org/en
Loek Peeters
HumanSurge is a global emergency roster for humanitarian responders.

Powr of You - https://www.powrofyou.com
Keshav Malani
Powr of You is a personal data marketplace.