Craigslist has pretty much claimed classified ads, winning out over newspapers in a big way. But start-up EcoFlip is challenging Craigslist, betting that consumers would prefer classifieds that focus on green living. With categories like "Solar / Wind," "Fuel-Efficient Vehicles," and "Rideshare," EcoFlip is definitely catering to a more specific niche than Craigslist.

The real question for EcoFlip's future is whether buyers and sellers will make the switch: Craigslist already encourages a recycling mentality. Options like FreeCycle do the same. The main selling point that EcoFlip has going for it is the clearer category system for those users looking to live a greener life. Finding a farmer's market on Craigslist can take some hunting, but it's an easy find on EcoFlip.

While EcoFlip offers free classifieds, just as Craigslist does, the new site is relying on advertising to support itself. That factor is going to make it a harder sell with consumers, but I think that EcoFlip has a chance to pull off its plan for a green classified site. Both of the company's founders, Forrest Kolb and Joe Paone, have entrepreneurial and financial experience — it will be exciting to see how they face the challenges ahead.

Image — EcoFlip