There's no content at the site, but you will find a Supporter Kit with Twitter icons and banners.

The site also mentions the game's Jump Festa appearance. Players will form a party of four and take on the "Jump Festa Tower" (which will presumably appear only in the Jump Festa demo) Those who sample the game will get this hat:

Sega made formal announcement of the game today with the Japanese online media, and also sent out some full res screens, which you can see here: