RTF is also always a good cross platform format.
PDF is a true metafile format, allowing merging of many different file formats into one. This does make it a bulky format, but it is truly cross platform and wysiwyg. The PDF is really powerful. Pretty much any kind of formatting along with media information can be stored in a PDF. For instance, color profiles can be incorporated with document to insure optimal presentation (for printing). Adobe still offers
online PDF conversion if you happen not to be able to create a PDF. (if your using an old text processer on OS 9 for instance), As everybody knows everybody has access to Adobe Reader for viewing PDFs. While the online service has all sorts of caviats, it is able to work with all sorts of file formats during the conversion.
RTF (rich text format) is not a meta file format, but it is a fairly universal format. I can't think of any modern word processors that can't decode this format on Windows (98 and better), Mac (10-), or Sun's Solaris OS. RTF is mostly wysiwyg, but as some formatting is not savable, but for the most part this isn't necessary. For most documents RTF is really the way to go, but that's just my opinion. Oddly, M$ created the format and probely dosn't use it as a default as anybody can decode and encode RTF documents with out paying M$ a dime. The Wav file format is the same, as well as a number of other standards and protocols that have become the defacto standard.
