The Sarah Silverman Program uses humor predominantly based on satirizing conventional family-friendly television shows.
I just think Sarah's brand of comedy works better in a club rather than on TV. She's funny at times but a little too (ok, a LOT brash) brash for some of us, especially the women that I know, personally, who have watched her spew/rant on her show.
One wonders, do you kiss your Mother with that mouth, Sarah? (It's a joke, kinda). :-)