Where can I get more information about flagging? What I understand there are two kinds of flags: one positive, the other negative. Is that right? Plus how do I use them correctly?
Αll of the flags are for reporting 'bad' posts. These are the available flags for a question:
All of them include an explanation and also, the names pretty much speak for themselves.
The same goes for the flags for answers:
There are less options here, but they are enough to review a bad post.
The 'positive' kind of flag you are referring to, as you did in this question:
Isn't exactly a flag. It's a way to save your favorite questions, so as you can find them easier in the future.