PPAs are personal package archives that allows users and groups on Launchpad to make packages available to the public. PPAs can be added with a terminal command or through Software Sources.

A PPA is a personal package archive generally hosted by launchpad.net. PPAs allow developers to distribute software in a manner similar to Ubuntu repository items using apt-get.

Users can add a PPA to their system with the apt-get add repository command or through the Software Sources application. This allows users to install, update and remove PPA packages just like regular repository packages.

You can use the ppa-purge command to remove a PPA, or you can remove it through Software Sources.