Technorati Authority Needs Categorization

Yesterday, I noticed that Technorati replaced "X links from N blogs" with Technorati Authority numbers. My TA is 542 which isn't bad for just having a habit and a temper. Their use of the word authority is questionable but then words can be stretched like spandex pants as long as no one is wearing them (read trademark) so I won't complain.
However, I think lumping every subject into one basket degrades even the loosy goosy way Technorati is using the word authority. They need to categorize authority by subject of interest so that authority in technology is different from authority in fashion.
There are many ways to do this but I think the simplest approaches are opt-in, leaving over-all authority as General Authority. Let blogs spell out what their subjects are with natural penalties for blogs covering too many subjects to curb abuse. There are many variations and tricks that can be thrown to spice it up a bit. To get it started, open a wiki to let people fight over the list or hierarchy of categories.