Many of the Kickstarter supporters mention how long they've waited for Do to finally be available for purchase. One thing's for sure, I've been developing Do off and on for a loooong while. From 2007, it's been an open and transparent process. Throughout that time, we've gone through many revisions, playtests, and brain-blocks. Here are some things I've learned about developing in the open and how that may have helped Do's Kickstarter support.
Progress Comes in Many Forms: My process of game development builds up many, many visual artifacts. I took pictures of scratchy notebook pages and index cards as they piled up, to keep myself accountable to the public at large. I also posted letters, actual play reports, and a TON of Liz Radtke's art.
Some Will Be Disappointed, More Will Appreciate The Progress: When you post any kind of document that gets people playing, and then later on you change a critical rule or mechanic, you'll get some disappointed people. This will make you question your current direction and lead to building a bloated, over-burdened game. Just remember to follow your vision. This game is not done yet and everyone knows it. You may lose some interest when you change a rule, but you'll gain more faith in yourself that you're really making progress.
Know When You're Ready: A couple years ago, I sent in a little ad for Evil Hat to insert in the back of Chad Underkoffler's Swashbucklers of the Seven Skies. I figured, hey, it's a game about big open skies, so there would be crossover interest for my game. Indeed, there was, but I was still very premature in sending out that ad. There have also been times where I called for playtesters before a playtest doc was complete and then had to delay or cancel those sessions. This made me anxious about Do appearing to be vaporware. Avoid those fears. Make sure you have goods to deliver before making any promises.