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?