This looks like a different sort of categories than I'm used to? Is it possible for the users to make more categories? Anyway, I will post this message in 2 categories now, sub and subsub.
OK, I'm sure we get used to this, even if it is different But - is it possible to have categories box om users blog page too? If I'm reading a persons blog, I might want to se what this users have posted ex. in category "Perennials 2008"