Seattle-based Zillow and Yahoo! said today that the two have extended their advertising deal on the Yahoo!-Zillow Real Estate Network. The two, who have been working together since February of 2011 on the unified ad network, said the continued deal will let real estate agents and brokers place ads across both sites with a single phone call. Details on the advertising deal extension were not announced. Zillow's deal with Yahoo was brokered in July of 2010, as Yahoo offloaded advertising a number of advertising efforts at the firm. Yahoo moved its real estate advertising management to Zillow, and its online display ad efforts to Bing, after Yahoo gave up on trying to handle its own advertising.