Like every network before it Walt Disney Co.'s (NYSE:DIS) ABC is trying to squeeze every nickle out of a hit show. Investors, though, shouldn't expect too much from the spin-off of "Grey's Anatomy."

Spin-offs have a mixed track record. General Electric Co.'s (NYSE:GE) NBC tried to capitalize on the success of "Friends" with "Joey", a mediocre sitcom that failed to excite audiences. The "CSI:Crime Scene Investigation" and "Law and Order" shows are successful because they have different casts. Of course, some of the most popular shows of all time were spin-offs including "The Jeffersons," "Mork and Mindy" and "Lou Grant" got their start from other shows.

But these shows are ancient history. These days, shows based on characters from other programs are rare, which is why ABC's bet on "Grey's Anatomy" is interesting.

The new show will feature Dr. Addison Montgomery-Shepherd, a popular "Grey's Anatomy" character played by Kate Walsh, The Wall Street Journal said. Basing a show on a flawed obstetrician is a good idea. ABC obviously is aware of the popularity of TLC's "A Baby Story." If it's good it will attract advertising dollars and give the network a profitable franchise.

But it's far from a slam dunk.

"Grey's Anatomy" came quite close last week to "jumping the shark" with its ridiculous two-part episode featuring a ferry crash. The main character Meredith Grey fell into the cold water after being rescued by McDreamy. Come on? Does anyone not think she's going to survive? I mean it's too late to change the name of the show.