So far, only 13 states and the District of Columbia have told the Obama administration they intend to set up the insurance exchanges that are supposed to provide a marketplace for people to buy health plans. None are being watched as closely as California, whose singular challenges, from the size, diversity and geographic spread of its uninsured population to its vast budget problems, make it stand out. Many feel a successful rollout here could convince other states with high numbers of uninsured residents that the law can be made to work for them.

“We are the example,” said Anthony Wright, executive director of Health Access California, an advocacy group. “If it can be done here, it can be done anywhere.”

The California Health Benefit Exchange has already hired 50 employees and is poised to hire 50 more. Construction of the Web portal through which some three million people are expected to buy insurance by 2019, and through which many others will likely enroll in Medicaid, is under way.

This fall, the board will seek bids from insurers to sell plans through the exchange, and it intends to have the portal up and running by next summer, several months before enrollment starts in October 2013.

Realizing that much of the battle will be in the public relations realm, the exchange has poured significant resources into a detailed marketing plan — developed not by state health bureaucrats but by the global marketing powerhouse Ogilvy Public Relations Worldwide, which has an initial $900,000 contract with the exchange. The Ogilvy plan includes ideas for reaching an uninsured population that speaks dozens of languages and is scattered through 11 media markets: advertising on coffee cup sleeves at community colleges to reach adult students, for example, and at professional soccer matches to reach young Hispanic men.