Rewards for Recycling
WM used "thinkgreenrewards.com" to encourage street-side recycling by awarding points which can be redeemed for coupons and products.
The system was integrated through webservices with various outside providers.
The difference to "greenopolis" was that this site here encouraged recycling using street-side pickup, whereas greenopolis had a lot of social media (blogs, videos), and encouraged kiosk based recycling. Maybe more deciding, both sides had different internal business units running them.