Anna's staff twitter was updated with this:
annastaff: 新たな新プロジェクト始動。忙しくなるぞー！楽しみ！ #Anna
It means something like: "
The start of a new project. We'll be busy! Enjoy! #Anna"
So a new project is coming... I guess is a new single!!! Can't wait for more news! If they're already talking about it it means we'll get news soon!
Source:
http://twitter.com/#!/annastaff/stat...91698586378240