Because in Japan, for a long time, texting basically was email.Or completely email-based, at least.See, Japanese cellphone software and contracts work a bit differently from what we know in the rest of the world. Whenever you get a new cellphone contract in Japan, you not only get a number but also a complementary, fixed e-mail address from the provider. And that address is at least as (if not more) important than the actual number when it comes to communicating with people.These email addresses are different from normal internet email adresses in that they are hard-bound to your cellphon...