Right now it's anyone's guess. Kori's translation suggests some kind of "of the day" feature. As we understand it right now, it's "today's number one board", whatever the heck that means. That's also assuming that "board" is even accurate... you probably can't trust this kind of thing to someone who doesn't speak a word of Japanese, LOL. Other kanji I saw that look similar are "cup" and "slope" .How about the possibility of "Forums"? (Community boards?)
So we'll just have to wait and see, either from a more knowledgeable source or from what SEGA actually puts there.