What do you do when you have a great idea for a product or service, something that will really make waves, and then out of nowhere, someone else announces something similar? You do nothing. You don't freak out and you don't give up. You just continue to push forward, using the competition as motivation, and wave to that chip on your shoulder as you continue to try to better execute the idea.

Because execution is the key. Ideas are a dime a dozen. You can be sure that if you have thought of it, so has someone else. But execution is what matters. It is what causes some to float to the top as others sink to the bottom. Try to understand what makes the idea so great, why people will find value in your idea, and ensure that the execution is a translation of just that.

I forget who said this, but it makes sense:

You should be less worried if some one else has the same idea, and more worried if no one else has the same idea.

I also think it's important to make the distinction between ideas and innovations. Innovations are not ideas, they are executions. Something is innovative because of the way it executed an idea, not because of the idea itself.

Was Flickr innovative? Yes. But not because of the idea. They weren't the first photo sharing website by a long shot, but they executed the idea in the best way up to that point. Because of that they were innovative.

Was Craigslist the first to think of classified ads? No, they stole the concept from newspapers. And even Yahoo had, and still has, a classifieds site. But Craigslist executed the idea in a way that best translated the value of the idea.

So the point is, don't put weight on the originality or the trendiness of an idea. Focus on the execution. Otherwise, you'll be constantly chasing a fickle, moving target. Have a desire and a commitment to execute the idea better than anyone else; cultivate the value from the idea, pursue innovative execution, and have the guts to take on the rest of the pack. Prove that your vision and your execution can and will float to the top.