What happened to ''Karen Sisco''?
Why do the networks take shows off so quickly? Also, wasn't ABC going to bring back ''Karen Sisco''? -- Tony
Unaired ''Siscos'' are being burned off on the USA Network (Wednesdays, 10 p.m.). But you're right: Nets want immediate hits (big ratings = big ad bucks) and yank too soon; there's always a cheaper reality show waiting to replace a quirky series. The nets do pay a price: Playing fast and loose with shows like ''Sisco'' partly explains why ABC is down 10 percent in viewers this year.
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