From http://www.nytimes.com/2008/01/20/world/asia/20japan.html:

What's a "cellphone novel"? The story describes them as novels
"composed on phone keypads by young women wielding dexterous thumbs
and read by fans on their tiny screens".

``Of last year's 10 best-selling novels, five were originally
cellphone novels, mostly love stories written in the short sentences
characteristic of text messaging but containing little of the plotting
or character development found in traditional novels.''

The top 3 were cellphone novels by first-time novelist.

``The boom appeared to have been fueled by a development having
nothing to do with culture or novels but by mobile-phone companies'
decision to offer unlimited transmission of packet data, like
text-messaging, as part of flat monthly rates.''

Bill