Question: iVillage, Inc. was owned by a media conglomerate headquartered in what building?

Context paragraphs:
Lagardère Group: Lagardère ] is a multinational media conglomerate headquartered in the 16th arrondissement of Paris.  The group was created in 1992 as Matra, Hachette & Lagardère and once covered a broad range of industries.  It is now largely focused on the media sector, in which it is one of the world’s leading companies.  Headed by Arnaud Lagardère, the firm does business in almost 40 countries and is structured around four main business lines: its book and electronic publishing division (Lagardère Publishing) includes the major imprint Hachette Livre.  The Lagardère Travel Retail unit includes store retail, largely in airports and railway stations while the Lagardère Active unit encompasses newspaper, digital media and magazine publishing (including Hachette Filipacchi Médias), radio and television broadcasting and production and advertising sales.  Lagardère Sports and Entertainment engages in sports and talent management, sports academies, event management, marketing of sports broadcast rights and management of sports venues.

ITI Group: ITI Group (International Trading and Investments Holdings SA Luxembourg), known as Grupa ITI in Poland, was a large media conglomerate headquartered in Warsaw, Poland.  On 2 July 2015, ITI Group and Canal+ Group complete the sale of their controlling interest in TVN to Scripps Networks Interactive.

Decca Records: Decca Records is a British record label established in 1929 by Edward Lewis.  Its U.S. label was established in late 1934 by Lewis, along with American Decca's first president Jack Kapp and later American Decca president Milton Rackmil.  In 1937, as a result of anticipating Nazi aggression leading to World War II, Lewis sold American Decca and the link between the U.K. and U.S. Decca labels was broken for several decades.  The British label was renowned for its development of recording methods, while the American company developed the concept of cast albums in the musical genre.  Both wings are now part of the Universal Music Group, which is owned by Vivendi, a media conglomerate headquartered in Paris, France.  The US Decca label was the foundation company that evolved into UMG.

The Walt Disney Company: The Walt Disney Company, commonly known as Disney, is an American diversified multinational mass media and entertainment conglomerate, headquartered at the Walt Disney Studios in Burbank, California.  It is the world's second largest media conglomerate in terms of revenue, after Comcast.  Disney was founded on October 16, 1923 – by brothers Walt Disney and Roy O. Disney – as the Disney Brothers Cartoon Studio, and established itself as a leader in the American animation industry before diversifying into live-action film production, television, and theme parks.  The company also operated under the names The Walt Disney Studio and then Walt Disney Productions.  Taking on its current name in 1986, it expanded its existing operations and also started divisions focused upon theater, radio, music, publishing, and online media.

Vivendi: Vivendi SA (formerly Vivendi Universal SA) is a French multinational mass media conglomerate headquartered in Paris.  The company has activities in music, television, film, video games, telecommunications, tickets and video hosting service.

IVillage: iVillage, Inc. was a media company owned by NBCUniversal.  The site focused on categories targeted at women, including Entertainment, Beauty & Style, Family, Food, and Health.  Additional businesses and brand extensions within iVillage Networks included iVillage UK, Astrology.com, GardenWeb, and the NBC Digital Health Network.  In addition, iVillage had a strategic partnership with BlogHer, a participatory news, entertainment and information network for women online.

NBCUniversal: NBCUniversal, sometimes referred to as NBCU or NBCUni and formerly written as NBC Universal, is an American multinational media conglomerate.  Headquartered in Rockefeller Plaza's Comcast Building (formerly the GE Building) in Midtown Manhattan, New York City, the company is one of two successor companies to MCA Inc. (Music Corporation of America), the other being Vivendi through its subsidiary Universal Music Group.

IVillage UK: iVillage UK is a British women's lifestyle website run by media company iVillage, owned by NBC Universal.

Grupo Abril: Grupo Abril (simply also known as Abril) is a Brazilian media conglomerate headquartered in São Paulo.  The company is the holding company of Editora Abril, which publishes the weekly newsmagazine "Veja."

Time Warner: Time Warner, Inc. is an American multinational mass media and entertainment conglomerate headquartered in New York City.  It is currently the world's third largest entertainment company in terms of revenue, after Comcast and The Walt Disney Company.  It was also once the world's largest media conglomerate.  Time Warner was first founded in 1990, with the merger of Time Inc. and Warner Communications.  The current company consists largely of the assets of the former Warner Communications (as well as HBO, a Time Inc. subsidiary prior to the merger), and the assets of Turner Broadcasting (which was acquired by the company in 1996).

Supporting paragraphs: IVillage NBCUniversal
Answer: Rockefeller Plaza's Comcast Building