.ppt, .pptm, and.pptx are file extensions of presentations created with Microsoft Office. It is also possible to create such a file in LibreOffice. Initially .ppt was not openly documented, however for the newer version (.pptx) there exists an official documentation. 

The presentations can be opened with Microsoft Powerpoint or Libre Office, where a presentation may also be modified. The formatting of a ppt. file may differ from the original if another version of Microsoft Powerpoint or another program was used to create it. The file can also be opened in the MicrosoftPowerPoint Viewer.

An object in PPT format is not suitable for archiving, but it is possible to save presentations as PDF. 

Advantages:

- pervasive

Disadvantages:

- proprietary