A bit of disturbance in the ad network force ... Sugar Inc. is taking its ad sales back in house after a year in a rev-share agreement that gave NBC Universal (NYSE: GE) roughly half of the take from the blog network in exchange for handling the ad sales. The contract allowed for termination in the event that Sugar reached certain metrics; last Wednesday, after running the numbers about ad sales costs versus revenue, CEO Brian Sugar did just that.

Sugar explained in an interview:  “From a size perspective, for every 100 dollars we sell, we essentially get $46 ... It wouldn’t cost $46 to sell. It’s a margin issue at this point.” He said the company quickly sold a $50,000 ad—“it’s $50 grand but we don’t have to give $25,000 of that to NBC.” He doesn’t expect it to be easy but says the company also has access to significant revenues from the acquisition ShopStyle.com. “Revenues were doing so well. We were trying to decide where best to invest the money.” They came to the conclusion that investing in increasing their ad sales was the best option.

No press releases like the original announcement last June. word of the change appeared first on the company’s own PopSugar blog; TechCrunch reported on it today, estimating ad sales at $10 million.

When I asked how much Sugar made this past year from advertising, Sugar quickly responded: “Half as much as we would have if we did it ourselves.” He was also quick to say he can’t provide the exact rev share beyond “roughly half.”  (Of course, they might not have reached the advertisers NBCU brought in or the same dollar amounts.) Does this have anything to do with the changes NBCU has implemented in that same year, including the launch of its Women@NBCU virtual ad network? Sugar initially was being sold through iVillage, which is now part of the larger network. Sugar says it shouldn’t be viewed as anything other than “a success story of a small two-year-old company that has grown faster than it thought it would.”

In fact, NBCU’s strategic investment in the online publishing company, announced at the same time as the ad sales deal, stands as does NBCU exec Lauren Zalaznick’s role on the start-up’s board. (Zalaznick is president, Women and Lifestyle Entertainment Networks.) But NBCU won’t be able to roll up Sugar’s numbers into its own any more.

• NBCU-Funded Sugar Publishing To Acquire ShopStyle.com
• Updated: NBCU Invests In Sugar Publishing; iVillage Will Sell Blog Network’s Ads, Roll Up Numbers