The Fuzion is a mid-sized car, like the Taurus, which it replaces. Ford has shifted from
Escort
Contour
Taurus
Crown Vic
to
Focus
Fusion
Five Hundred
Crown Vic
The Focus is closer to the Contour than the Fusion is. They are now missing a moderately sized sedan from the lineup, since the smallest grew (Escort -> Focus) and the mid-sized stayed about the same (Taurus -> Fusion).
Originally posted by Wikipedia:
The Fusion went on sale in October 2005 as a 2006 model, and is a replacement for the to be discontinued Ford Taurus.
The Fusion is a fat Mazda 6, which is really very comparable to the Contour. It's considered a full-sized sedan in Europe (like the Mondeo), but a bit small here. 
