Common Good: How (and where) can entrepreneurs and designers find meaningful problems to solve?

Stop trying to think so big and solve one little problem. Those little problems are what usually turn into big solutions. Starting the other way around, trying to solve a giant problem, almost never works. If you think there are gigantic problems like "solve death by creating a longevity cure" or "create infinite free energy", you'll need to start somewhere. How can you increase life by 1 year? 6 months? How can you prove it? What can you do to make an alternative energy (solar?) 50% cheaper or 50% more efficient? The alternative leaves you nowhere to go. Very, very rarely do we get giant leaps and when we do, they are almost always on accident. The only real alternative is when the government invests hundreds of billions of dollars on one small idea (Manhattan project, Apollo program, etc). Those too are rare. Start with one tiny idea to solve one little problem you see in a space you like and grow it from there. Shell, the oil company, was started with one oil rig and now invests massive amounts of money in alternative energy research. Google was just two guys who found a slightly better algorithm for search (which at the time no one really cared about) - now they're making self-driving cars. Twitter was started to help one guy send text messages to all of his friends at once to invite them to parties - now it helps start revolutions. Start small. Grow fast. And build a really big team that can help you take on massive problems down the line.

I don't think it works that way.  There are lots of unsolved problems out there.  Quite often they are unsolved because they are hard.  There's lots of people peddling mediocre solutions to ho-hum products.  Find something you can be passionate about.  That'll be the thing to go after.

Who judges these ideas? I assume you are thinking of a crowdsourced voting platform of sorts, where you upvote/downvote an idea after reading a 4 line description for half a minute? Am afraid but solving problems doesn't work that way. The only driver is you and your conviction. To find a problem to solve first find what you really love to do and spend time doing it. With enough time you will notice what needs fixing.

It's a bit like stand-up comedy, but not as funny. Observe the world around you, think about what bugs you, and instead of turning it into a great joke, come up with a potential solition for it. Though it would be great to combine both, so you have your pitch sorted, as well.

http://OPENIDEO.COM It is exactly what you are looking for.

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