Forbes Inc. has ambitious plans for an ad network with about 400 financial blogs as members, according to AP. The financial news media company is expected to release more details about its Forbes’ Business and Financial Blog Network on Monday, though it did say that the first participants include Xconomy and TalkingBizNews.

The company also said that it will handle ad sales across the sites with a system powered by San Bruno, CA-based Adify. And, as a way of perhaps lowering expectations, Forbes is shooting for an early revenue increase of 10 percent to 15 percent from the venture, even with the addition of hundreds of bloggers.

-- Contextually, the AP places the news about the Forbes’ financial ad ad network within a larger of piece that questions the competitive abilities of independent ad networks run by media companies like CondeNet, Martha Stewart Living Omnimedia (NYSE: MSO), Nickelodeon’s ParentsConnect Network, CBS’ (NYSE: CBS) network of local TV station sites, and the Washington Post (NYSE: WPO) (which, as the AP noted, ended its 16-member network this month, but plans to run feeds with ContentNext Media, paidContent’s parent, and others). The question: whether the creation of vertical ad networks can match the leverage of ad serving offerings by Google (NSDQ: GOOG), Microsoft (NSDQ: MSFT), Yahoo (NSDQ: YHOO) and AOL? The standard answer that smaller networks can more effectively target specific audiences came from Steve Woit, publisher of Xconomy, who told the AP: “A larger network, whether it’s Google or others, has to deal with every industry and large consumer sites.”

-- Viacom (NYSE: VIA) ad network additions:  In a guide to media ad networks AP also mentions that Viacom is creating a music ad network and another tailored to men’s lifestyle sites. The music ad network will operate under MTV, VH1 and Country Music Television and the male lifestyle net will be tied to Spike TV and Comedy Central.

-- IDG widget plans: In another separate ad network item, AP reported that tech mag publisher IDG will announce this week that it is working with Adify on a program called Widget Share, which will let media companies distribute headlines, video and other content to members of its ad network.

(Disclosure: We have an arrangement with Forbes.com to use and distribute some of our content.)

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