doc The .doc filename extension is a native file extension used by the closed source document processing application Microsoft Office Word. Initially developed and used by Microsoft since 1983, the filename extension .doc continues to be supported natively even in the most recent iteration of the word processing application Microsoft Office Word 2013. The more recent .docx filename extension however was introduced by Microsoft in Office Word 2007, becoming the default filename extension. Documents to be saved in the .doc format are saved as Word 97, 2003 documents.
rtf In its original conception, the .rtf format was a specification for formatting text and graphics principally designed to facilitate the interoperability of documents and text between Microsoft document processing applications. It eliminated the need for specialized translation software required to open documents in different versions of MS-DOS, Windows, and Macintosh. The specification is a proprietary filename format first developed by Microsoft in 1987 to be supported in Microsoft word 3.0 and all versions of Microsoft Office Word thereof. The latest revision, version 1.9.1, was released in 2008 and also marked the end of any further enhancements to the specification by Microsoft. Through unformatted text, control words, control symbols, and groups, a piece of text can be encoded into an .rtf format. All RTF readers then process .rtf formats by separating and acting on control information disparately from the actual text in the document. Though the RTF specification is proprietary asset of Microsoft, several non-Microsoft programs support both reading .rtf documents and creating .rtf. Microsoft Office Suite is still however the most dominant application associated with this specification.