"One of my top tips for aspiring entrepreneurs: Tell everyone you know about your idea. This runs contrary to the instinct that most people have, because they're afraid someone is going to 'steal my ideal.' Ideas alone are worth very little, it's in the execution and market feedback that companies are made.
The original idea before Mint was a life and goal planning system I called Carpe Viva. The idea was that all of life's goals, from buying a house, getting an MBA, or learning Spanish could be quantified in both time and money. Rather than keep this idea to myself, I went out and asked everyone I could -- from my friends and family to strangers at the train station -- about the concept. In about 80 conversations, only one person actually thought they'd use the product -- it was just too difficult and too bizarre to try to plan your life out over the next 30 years. At the same time, the money and savings side of the idea resonated with people -- most were having difficulty saving and planning for long term goals, and back then present desktop personal finance tools and online banking were insufficient or too difficult to use.
End result: I saved myself from starting the wrong company, with the wrong product, and gained some of the key insights that made Mint.com's personal finance budgeting, tracking, planning, and goal setting systems possible. Tell your idea to whomever will listen and you'll get valuable market feedback before writing a single line of code."