Mixi Requires a Mobile Email Address for Registration!

Seems that Japanese social networking site Mixi now requires you to have a Japanese mobile phone email address to register! I invited a friend (who happens not to have a mobile phone) and was very surprised to hear that the registration form, even if you have been invited by a friend, requires a mobile email address. The form checks that the address is one of those used by the major carriers here (e.g. @docomo.ne.jp). You have to click in the links in the emails to both the mobile phone and PC address in order to verify the account, so you can't use a fake one or keep your mobile email address private even if you choose to. Unbelievable! I wonder if you can delete or edit the address once registered???

Guess we are facing a 'mobile divide' here in Japan, although having said that you have to have a regular email address as well so that's not the only problem.