I've been looking into writing an text translator (.rtf specifically), but I've encounter some problems. The crux of the problem is this: The default media format for text is plain ASCII.
This seems to limit the usefulness of text translators because all of the fancy formatting information of most document formats will be lost. Any application that wants to support the extra formatting information will have to support the document format directly since the default media format doesn't. It seems to me that pretty much defeats the purpose of a translator.