For Japan's publishing industry, which has endured a decade of declining sales, the boom is "a savior," says Satoshi Iwamoto, the general manager of Net Media Center at Shogakukan Inc. The market for digital publishing grew nearly fourfold compared with the year before, to $38.5 million in March 2006, according to Impress R&D, a Tokyo-based research firm. Comic books account for $19.6 million, compared with $9.4 million for comics on PCs.

Mobile comics, for which viewers pay 30 or 40 cents an episode, are also a boon to Japanese carriers, whose customers are shifting to fixed-rate plans.