[tTarnMhrkm]

You're right that for a simple utility, brand can be a tough moat to build, and speed of innovation is definitely a huge part of the equation. My bet is that it's a combination of continuous innovation and a relentless focus on the user experience. The clones can copy a feature list, but it's much harder for them to copy a thoughtfully designed, native-feeling GUI and responsive customer support from a developer who is actually engaged.