I started https://pledgebalance.com/ in February and just launched an iOS beta group this month. It's an app to balance the negative impact of your daily travel with tiny payment that goes 100% to carbon offsets. My drive today was 17¢ to balance, which is invested in projects like planting trees.

Only $50 of revenue this month, but hopefully will grow quickly from there. Also will add premium features like corporate accounts for additional fees, though will never take a cut of a person's balanced travel.