NEW YORK -- Apple Inc. Chief Executive Steve Jobs said Monday that the company's iAd platform, its mobile advertising network, will go live on July 1, introducing yet another disruptive force in the media industry.

The rise of digital advertising already has weighed heavily on traditional media businesses--such as publishing, radio and television--and the nascent mobile market is expected to bring a new wave of upheaval as devices like Apple's iPhone and iPad proliferate.

Mr....