Doc (an abbreviation of document) is a file extension for word processing documents; it is associated mainly with Microsoft and their Microsoft Word application. Historically, it was used for documentation in plain-text format, particularly of programs or computer hardware, on a wide range of operating systems. Almost everyone would have used the doc file format, whenever you write a letter, do some work or generally write on your PC you will use the doc file format. It was in the 1990s that Microsoft chose the doc extension for their proprietary Microsoft Word processing formats. As PC technology has grown the original uses for the extension have become less important and have largely disappeared from the PC world.
Early versions of the doc file format contained mostly formatted text, however development of the format has allowed doc files to contain a wide variety of embedded objects such as charts and tables from other applications as well as media such as videos, images, sounds and diagrams. doc files can also contain mail merge information, which allows a word-processed template to be used in conjunction with a spreadsheet or database.
AbiWord Apple Pages AppleWorks KWord Microsoft Word StarOffice
The file type .mobi is an eBook format created by a French eBook company called Mobipocket which created a free software application for multiple devices including PDAs, smartphones and tablet devices. The company was bought by Amazon in 2005 and the support of the .mobi file extension was officially discontinued in 2011 with the AZW format superseding it.
Amazon Kindle Apple iBooks Mobipocket Reader Desktop