16th
I originally made it for myself, because I had a need for it, and I didn’t even tell anyone else about it for months. It ended up being useful to other people, but that was a fortunate side effect. When it came time to make an iPhone app, I made my own dream app to satisfy my needs, and the same thing happened: it was adopted by other people who had the same needs.
Solving something for you is often solving something for others. Do it for you, and not for anyone else… and you may build a business upon it.
I cannot agree more about how Marco is developing his application. Yes, he listen to his customers, but he’s doing the application for himself first and it’s giving him a horizon to follow, a ground to return to.
Instapaper is so useful, that I will consider buying an iPhone for that application alone. I use it even more than the actual phone!