Comment by toyg

Maemo was debian-based and built around GTK. Its device target was effectively the N900. Nokia then rebuilt the interface (at fantastic dev speed, it has to be said) in QT (which had been blessed as the UI framework in order to facilitate onboarding of Symbian developers, who had been told to use Qt for new Symbian apps) and shipped it in the N9.

By then, however, management had struck an agreement with Intel to join forces over a Linux OS for devices. Intel had its own Linux distro, Moblin, which was based on RedHat. Moblin and Maemo were meant to merge into "MeeGo", a distro based on RedHat but with a QT interface. The project started fairly quickly but, by then, the N9 was basically ready, so Nokia effectively shipped what they had beforehand and just called it MeeGo.

Beyond the UI, iirc, the differences between Maemo and Moblin/MeeGo were the packaging system and some service daemons. The most annoying part, really, was that third-party apps built for Maemo would have had to be repackaged and retested for MeeGo, effectively throwing away all community efforts made over several years. Despite the best efforts by Nokia to placate folks, the community they had built around Maemo was completely pissed off and largely gave up, focusing on the actually-profitable systems. And then the burning platform memo happened.