The Portland Project is an initiative by freedesktop.org aiming at easing the portability of application software between desktop environments and kernels by designing cross-platform APIs and offering implementations thereof as libraries to independent software vendors (ISVs).
The project was taken to establish a greater foothold of Linux and other Unix-like operating systems in the desktop market.
It aims at resolving a number of key factors that are believed to reduce the adoption rate of Linux distributions as operating system of choice for desktop computers at home or in the office.
While the Tango Desktop Project was started to give users a more unified graphical experience, the Portland Project is intended to ease the porting of desktop applications to Linux for independent software vendors (ISVs).
The project goal is to let software developers worry less about the desktop environment a distribution is using, and thus bring it on more common ground with Microsoft Windows and macOS in this particular area.