When it comes to upfront choices for cable TV advertisers, there are certainly plenty of shows, but not necessarily many new ideas.

In back-to-back days last month, Oxygen announced it is developing a show called "Thrift Wars," which follows hardcore thrifters in New York as they scour the city for vintage fashions and try to make a profit, and Travel Channel announced the program "Baggage Battles," which focuses on people who compete to buy unclaimed airline luggage at auctions.

The programs will have plenty of competition. In January, four cable networks aired about 10 programs in the auction/pawn/repossession/pickers category, according to a report to be released today from CableU, which studies the cable industry. History has "Pawn Stars," "American Pickers," "Cajun Pawn Stars" and "American Restoration"; A&E has "Storage Wars," "Storage Wars Texas" and "Shipping Wars"; truTV has "Hardcore Pawn" and "Storage Hunters"; and Spike has "Auction Hunters."

These series were cablecast a total of more than 200 times during the month, with most airing between 14 and 17 times, according to CableU. "Pawn Stars" and "Storage Wars" had 46 and 57 telecasts, respectively.

There are more than 30 series in this category across cable. There's also a growing fascination with swamps, logging, housewives, hoarding and hand-fishing.

Duplicate content isn't a new phenomenon. It stretches back to Westerns, police dramas, talk shows and reality singing competitions. But media experts agree that the recent reality fad appears more extreme because of the specificity of their content, and that it's hard to tell one show from another.

The knockoffs typically don't perform as well as the originals. According to CableU's study, which uses custom Nielsen-generated data, over 2 million viewers watch the prime-time telecast of the original "Pawn Stars" and "Storage Wars," but it tapers off to about 600,000 viewers as you move further down the list of shows with similar premises.

"One thing becomes clear: The leaders into this genre -- History and A&E -- continue to perform well above the followers, truTV and Spike," said CableU CEO Gary Lico. "The lesson to programmers is to keep pushing innovation and novelty for breakout ratings success." From an advertisers' perspective, there's some security in the replicas, even if they aren't as successful, said Brian Wieser, media analyst at Pivotal Research Group. "Advertisers know what they are getting. While it is unlikely the copycat will be a runaway success, they are certainly salable."

Though not necessarily as expensive. "Networks want to charge a high [cost per thousand] for the knockoff based upon what the original did, but it is up to us to determine the appropriate rating and negotiate a CPM," said Marc Morse, senior VP-national buying at RJ Palmer.

Lyle Schwartz, head of Implementation Research and Marketplace Analysis at Group M, said, "If multiple networks begin to attract the same type of audience, for buyers it becomes purely about efficiency and where you can find the same spot" for less.

Another threat could come from cable and satellite providers, which may start taking a harder look at how these programs will affect negotiations when it's time to renew affiliate deals. "Cable operators should be more concerned about the lack of differentiation," Mr. Wieser said. "Operators want channels because they contribute something that is different than the rest of the package. If you are a network trying to convince [operators] to pay a 10% increase next year, you don't have much leverage in negotiating affiliate fees if there are several mirror channels from different parent companies."

Maureen Huff, spokesperson for Time Warner Cable, said that , in deciding what channels to carry, it looks at ratings and set-top-box data as well as at "whether the programming is unique and compelling to our customers." As cable operators expand low-tiered packages, such as Time Warner 's TV Essentials, low-rated and "copycat" networks could become the casualties that save consumers money, said Brad Adgate, analyst at Horizon Media.

"When a channel is dropped, one of the talking points is 'Can viewers get this elsewhere?'" said one cable insider. "Networks will lose leverage when negotiating affiliate fees."

Travel Channel and Oxygen believe their recently revealed programs are different enough -- and that niche programming will find niche viewers.

"It's a fresh take on the subject," said Laureen Ong, president of the Travel Channel Media, comparing "Baggage Battles" to "Storage Wars." "We are going beyond what entertainment networks do" in helping viewers learn what to do when they've lost their luggage, she added. As Susan Malfa, senior VP-sales for Bravo Media, Oxygen Media and Women at NBC Universal, justifies "Thrift Wars": "There are a ton of cars in the market, but each one has special features that fulfill the needs of a different customer."