The aforementioned Barbarian Group worked on a project for CNN called Headline t-shirt project a few months back. They explain it better than I would here.

Brand Tag

Again, I know that this is a little old...
Noah Brier who is the head of planning and strategy at interactive shop, The Barbarian Group (Subservient Chicken anyone?), created this Tag Cloud website for brands. Find a brand, tag a brand, compare it to what everyone else thinks.