Part of making a desktop operating system that people feel immediately comfortable with is ensuring that software installation is as easy and familiar as possible. PC-BSD has taken this approach when developing the PBI (PC-BSD Installer or Push-Button Installer) file format.
Programs under PC-BSD are completely self-contained and self-installing, in a graphical format. A PBI file also ships with all the files and libraries necessary for the installed program to function, eliminating much of the hardship of dealing with broken dependencies and system incompatibilities.
PBI files also provide developers and packagers with advanced scripting and user interaction in an entirely graphical format, making the entire install procedure similar to what a user would expect from other popular graphical operating systems.