mobi The .mobi filename extension is an eBook file format developed by French company MobiPocket for their ebook readers for mobile phones and PDAs. The company was later acquired by book reseller and online store company Amazon in 2005, a deal which included the mobi format asset. The mobi file format is mostly associated with the mobipocket software package as well as early versions of Amazon's kindle ebook reader device. The format is considered cross platform given its compatibility with several devices including most smartphones that have compatible readers installed. But although mobi files still exist in circulation, the format was superseded by Amazon's AZW format when support and further development of mobi ceased in 2011.
lrf The LRF format is a proprietary format developed by Sony in collaboration with Canon, as a document and text encoding standard for the Broad Band eBook file format. The format specifically targeted Sony portable eBook readers and was capable of encoding both text, pagination, and images. Being unencrypted, LRF encoded files do not enforce DRM. This is in contrast to the LRX format which is also part of the BBeB eBook file format which does support encryption for DRM files. The Sony eBook store announced in July 2010 a discontinuation of support for the LRF format in favor of the public and open EPUB format.