It’s always fascinating to read an insider’s perspective, and doubly so when it comes from someone whose day job is industry analysis. That combination makes John Gruber’s postmortem of Vesper on Daring Fireball all the more interesting for those curious about what makes some apps succeed and others fail. Vesper was a note-taking app developed by Q Branch, a company made up of Gruber, designer Dave Wiskus, and developer Brent Simmons, who is well known for apps such as Glassboard, MarsEdit, and NetNewsWire. Gruber attributed Vesper’s failure to generate enough revenue to bad timing with regard to iOS 7, shipping the iPhone app before the Mac app, competition from Apple’s Notes, and not switching to a subscription model. His evaluation should be required reading for any developer considering making a productivity app for the Apple ecosystem.