Subject: On television, why do sitcoms look different than movies?

When watching TV, I've noticed that some programs (sitcoms, talkshows, cheap 
commercials, etc.) have a slightly different look than others (movies, 
high-profile commercials, high-quality programs). The first group has a 
sharpness to the picture, while the second group looks softer. Is this simply 
due to the use of different filters on the cameras, or is there a 
post-processing procedure done to the movies & etc.? (Or am I just nuts?) ;)

Re: On television, why do sitcoms look different than movies?