Plenty of good info, but it seems a regurgitation of everything on spyderco's website. No opinion in it, I don't know if that's good or bad just saying. Small thing, it's the "good" instead of "well". keep at it I say!
With certain steels you can get ebony black with vinegar/ferric chloride. I don't know how the durability stacks up to cold blue though; the oxidation from the ferric chloride is tougher than oxidation from vinegar.