Mobipocket files purchased from Amazon have an AZW extension (which presumably stands for Amazon Whispernet – the name of the Kindle wireless download service). Mobipocket files from other sources will have a MOBI or PRC extension. Topaz files will have an AZW1 extension if downloaded directly to the Kindle, and a TPZ extension if downloaded from Your Media Library on Amazon.com.
ReadWriteWeb has a brief survey of mini serialized novels in the U.S.:
In Japan, mobile phone novels called “keitai shousetsu” have become so successful that they accounted for half of the ten best-selling novels in 2007. Here in the Western world several would-be novelists are attempting to use Twitter to create the same phenomenon. Some of the novels tweeted so far have been interesting and engaging, but others, sadly, appear to be abandoned. Will micro-format fiction ever take off here as it did in Japan?
Wholesale trade ebook sales accounted for $4.9 million in June ’08, according to industry stats from the Association of American Publishers (AAP) and the International Digital Publishing Forum (IDPF). This is an 87 percent increase over June ’07. Year-to-date ebook sales are up 43 percent over last year.
Note: The AAP/IDPF stats aggregate information from 12-15 trade publishers and reflect wholesale sales figures in the U.S.