A recent Quora thread has entrepreneurs chattering about an interesting challenge: name some startups with really unique business models. How do you create an "out there" business plan that's also sustainable? It's certainly not as easy as it looks. But here are three examples, courtesy of the Quora community, as food for thought:

Friendsurance

By spreading out risk between friends and family, Friendsurance holders can save up to 50 percent on their insurance costs. The shared insurance pool means that users are less likely to cheat with their money, according to Quora user Kristoffer Tjalve, a former employee at Board of Innovation.

Duolinguo

An online language program, startup Duolingo teaches you basic vocabulary, grammar and sentence structure through games and motivational hearts. (Cute.) It's completely free, and makes money by pulling thousands of web translations and merging them to create almost flawless, human-like ones. Check out the founder's TED talk to learn more. 

India's UC: The "Pay Donation" method

The Indian non-profit startup UC (United Care Development Service) starts by funding its own project. Once successful, that project is then "sold" to donors to raise money for future ones. Their motto? To generate "Resources by Result." 

What are the most unique business models that you're seeing? Join in on the Quora conversation and chime in. 

Published on: Aug 29, 2014