Если кто давно хотел
аннигилировать в Генезисе все свои NXT (или часть из них), но всё не доходили руки - следует поторопиться, Жан-Люк
написал, что начиная с версии 1.4.0 такой способ похерить свои NXT будет невозможен :-))
Allow sending messages with no recipient.
These transactions will be included in Blockchain?
Yes, those are normal transactions. It is to be used for arbitrary messages that are really public announcements and don't have a single intended recipient. Currently some people are using Genesis as recipient presumably for such purpose, but this will be disallowed after 1.4, just like other transactions with Genesis recipient have been changed to use null recipient.