Synergy, with its promise of coordinated acquisitions and intracorporate partnerships, has been hailed as one of the biggest advantages of conglomerate publishing. And Viacom, where cable and broadcast networks frequently supply content to—and reinforce the books of—Simon & Schuster, has been one of its biggest practitioners.

But new questions about synergy emerged after last week's announcement of a Viacom split. The move has important pipelines like MTV and Nickelodeon becoming part of a company separate from S&S, beginning in 2006.

In the short term, said executives, it's unlikely that anything would change, thanks to existing contracts. But the long-term is murkier. Without the more intimate relationship with the networks, will new deals for brand-based books become less likely? And without the in-house knowledge of TV promotions, does it become harder to schedule book release plans? If it's the beginning of something that could have echoes—rumors surfaced last week about one company scoping out the Time Warner Book Group for purchase—we could be seeing the beginning of a new rollback of the conglomerate synergy model (de-nergy?).

So what's most susceptible to change? Pocket and MTV Books have enjoyed a remarkably fruitful joint venture that has seen the publisher get a jump on properties the network knows will be (or will help become) big. (See 50 Cent, whom the house signed years before his breakout.)

"It's a very important joint venture financially and creatively," said Pocket Books publisher Louise Burke. Burke declined to specify the length of the MTV deal, but it's reasonable to wonder if MTV would open its desirable brand to outsiders once the contract is up.

Meanwhile, Pocket's agreement with the WWE benefits from programming on Viacom cable network Spike. (Sources said the wrestling deal was recently renewed for three years.) And on the children's side, Nickelodeon franchises like SpongeBob Square Pants and Blues Clues have become a significant revenue stream.

(It should be noted that even at Viacom, one piece of synergy's great promise has rarely been realized: books bought by a publisher and developed into in-house TV and film productions.)

For his part, S&S CEO Jack Romanos said that even as separate entities, S&S will pursue multimedia deals with the cable networks. But he also sought to play down, retroactively, how close the publisher and cable networks have been. "We operated more like cousins than sister and brother," he said.

At S&S, the possibility of big TV exposure—even if it's just a matter of perception—can help land books, as authors can be tempted by just the thought of, say, a 60 Minutes interview. But in this regard, at least, no change is expected: CBS is staying on the S&S side of the family.