It is an alternative format to the DOC file type supported by Microsoft Word. RTF files are ASCII text files and include embedded formatting commands. RTF files do not contain macros and cannot be infected with a macro virus. This makes RTF files a good document format for communicating with others via email. However, some macro viruses attempt to intercept saving a file as an RTF file and instead save it as a DOC file with an RTF extension. Users can catch this trick by first reading the file in a simple text editor like Notepad. DOC files will be nearly unreadable, while RTF files will be readable.