Its simple. Many of us only want to know certain things about Brawl. Here you can ask about a spoiler, and hopefully someone who has heard about it [post Japan release] or completed it [post US release] will respond to your question. Here you don't have to worry about getting too much information, because you're the one asking the questions.
This thread will remain open after both the Japan and North American release, because I'm sure some of us will have questions throughout both.
I'll start off: I want to know how many playable characters there are, in total, including all secret characters. I just want to know when I've unlocked everyone, so all I need is a number.