Advertising Roundup: Omnicom Downgraded; Valassis Pulls Out of Plain-Dealer; Walmart Adds Riney; More ...

(MoneyWatch)  S&P downgrades Omnicom's credit -- Standard & Poor's today placed its long-term ratings for Omnicom Group, including the 'A-' corporate credit rating, on "CreditWatch with negative implications." [Source: Adweek]

Valassis ends RedPlum deal with Plain Dealer -- last weekend, Joe Daugirdas, also known as "The Coupon Guy," noticed that all the usual coupons from a company called "RedPlum" were missing from the Plain Dealer, the News Herald and the Lorain Morning Journal. It turns out that the Valassis Company, owner of RedPlum, has decided to stop inserting those coupons in the Cleveland area. [Source WKYC]

Mandel out at Nielsen -- Jon Mandel, CEO of NielsenConnect, has left the company. NielsenConnect, a business unit of Adweek parent the Nielsen Co., was formed two years ago to create new services, drawing on information from the dozens of Nielsen units that collect, analyze and report on consumer patterns and usage around the world and provide that information in new and unique ways to clients. NielsenConnect will also be shuttered as a formal entity after creating several new businesses. [Source: Adweek]

Walmart taps Hal Riney -- Walmart has expanded its agency roster, tapping West Coast shop Publicis & Hal Riney to refresh the retailer's Great Value brand, according to industry executives. [Source: Ad Age]

Lamar testing solar-powered digital billboards -- The proprietary digital technology uses solar power and light-reflecting digital ink instead of light-emitting diodes Lamar Advertising is testing a new digital billboard technology that could provide a strong alternative to the digital billboards populating the country. [Source: Adweek]