Boris Veldhuijzen van Zanten, founder of Twitter Counter, Spread.us and The Next Web
The product was a failure.
We found out pretty quickly after we launched and soon had a meeting with the group of informal investors who funded us. We explained to them what happened and offered two options. 1: we could keep on developing, try to find a solution and work on it for another year or two. Or, the second option, we could kill the product and return most of the money ( a bit more than 50%) back to the investors.
We are very proud that we had the chance to successfully show that this particular solution didn't work. Of course we would have preferred it if the solution would have been perfect, but at least we had the chance to give it a try.
Great approach, and only possible when you see the business as the secondary item, and you (the entrepreneur) as the primary driver. Those who advocate that your startup should take over your life would probably not be able to take this step.