California’s high-tech firms make the world’s most popular smartphones, social networks and search engines, but there’s one asset they’re struggling to build: trust.

The vast majority of Californians surveyed in a statewide poll are worried about the data collected by Internet and smartphone companies, and most said they distrust even firms known for their ardent fans and tens of millions of daily users.

Many of those surveyed in the latest USC Dornsife/Times poll also said they were wary of firms collecting personal information without their knowledge and concerned that personal data could become public or be harvested to sell them products.

The results of the survey, which draw a stark picture of the public’s attitude on privacy, come as policymakers ramp up efforts to pass laws aimed at protecting personal information on users’ whereabouts, interests and social activity. In recent months, federal lawmakers have held numerous hearings about the need for privacy laws, and Obama administration officials recently renewed their call for Congress to pass online privacy legislation.

“It reaffirms my opinion that privacy is a big deal — and it’s becoming a bigger deal,” Rep. Joe L. Barton (R-Texas) said of the poll results. Barton, who cosponsored a privacy bill pending in Congress, said lawmakers are “gaining ground” in their years-long battle to write data privacy into law.

The findings of the survey, conducted for the USC Dornsife College of Letters, Arts and Sciences and the Los Angeles Times, were consistent with a poll released last month by the Pew Research Center, which found that 68% of respondents did not approve of targeted Internet advertising if it meant having their online behavior tracked and analyzed. Pew has said that nearly 3 in 4 Americans now use search engines, and two-thirds use social networks. Nearly half of adults in the U.S. own smartphones.

The USC Dornsife/Times poll revealed that the rise of digital culture is mirrored by Californians’ sense of the technology industry’s importance to the state economy, with 65% of those surveyed saying the technology business was more economically important than the state’s other marquee industry, entertainment.

But the increasingly central role of technology in the lives of consumers did little to inspire trust in Silicon Valley’s star companies. Respondents were asked to rate six on whether they trusted the companies to be responsible with personal data. On a 10-point scale, with zero meaning no trust and 10 meaning complete trust, none scored above five, and most hovered around three.

Apple was highest with a mean score of 4.6, followed by Google at 3.8. LinkedIn scored 3.0, while online video site YouTube was rated 2.8. Facebook was next to last, with a score of 2.7, only slightly above Twitter at 2.4.

“I thought the ratings were strikingly low,” said Linda DiVall, the president and founder of American Viewpoint, one of the polling firms that conducted the survey. “If I were involved with the branding image of those companies, I would be very concerned.”

DiVall said that the public tends to have low regard for most government, religious and business institutions — but that people give the lowest ratings to organizations with which they have the least direct contact. In the case of companies like Apple, Facebook and Google, however, many consumers use their devices and websites every day.

The poll was conducted by telephone March 14-19 with 1,500 registered California voters. It has a margin of sampling error of plus or minus 2.9 percentage points.

None of the companies mentioned in the survey would comment on the results of the poll.

But Linda Woolley, a representative of the Digital Advertising Alliance, an industry marketing consortium supported by hundreds of Internet, automotive, financial and healthcare firms, said the poll results were not telling the whole story.

“If somebody came up to me on the street and said, ‘Are you concerned about online data practices?’ I’d say yes,” she said. But, she said, most people would be thinking of problems like identity theft and credit card fraud rather than what most firms use the data for: to more efficiently sell people products they want.

“I don’t care whether you’re in the hotel business or the travel business, or selling soap — every company is talking about personalization,” she said. “What data enables you to do is cater to the customer and really make them feel like you’re taking care of them.”

Of those who said they were concerned about data privacy, one-quarter said they were most uneasy about their personal information being collected without their permission or knowledge, while 21% said they were more worried about their information becoming public. A smaller group, 18%, said their chief concern was either that companies could use their personal information to make money or that they would sell it to marketers. Nearly one-third said they were equally concerned by all of these possibilities.

Andrew Hanson, 23, a warehouse manager in San Clemente, said he believed companies’ use of personal data worked in consumers’ favor.

“I don’t look at it as an invasion of privacy. I look at it as almost like extreme marketing,” he said. “They’re just trying to get advertising out there, and if anything, it’s helping me out.”

But most were wary about the growing ability of companies to monitor — and monetize — a variety of consumer behaviors.

“What I do is nobody’s business but my own as long as I’m a law-abiding citizen,” said Gloria Maldonado, 70, a retired teacher in Redwood City. “I’m very concerned about the overreach.”

Privacy controversies continue to trip up the companies most closely associated with the digital revolution.

In March, when Google rolled out a privacy policy that allowed it to collect and share user data from across its search engine, email, video, mapping and other services, the move was widely criticized. The critics included a group of federal lawmakers who questioned whether Google’s users would be able to prevent the company from collecting data about them.

In February, popular social media services including Twitter, Foursquare and Instagram acknowledged that they were reaching into users’ smartphones and grabbing personal contact information without explicit permission. Many of the companies changed the way their applications worked to make the data collection optional.

And last April, researchers discovered that Apple’s iPhone kept a detailed log of its precise whereabouts, storing up to a year’s worth of user location data. The company altered the phone’s software so it stored a much smaller cache of location data.

Conscious of the rising tide of privacy snafus, legislators have proposed more than a dozen privacy bills, but none has made it through Congress.

Rep. Edward J. Markey (D-Mass.), who along with Barton of Texas introduced a bill last May to protect the personal information of children online, acknowledged that widespread privacy concerns have not stopped millions from using the services that are monitoring their online activity.

“People drove automobiles before there were seat belts or air bags,” Markey said. “But as time progresses, in the same way you can have both automobiles and safety, you can have the Internet and privacy — and I think that day is arriving.”

david.sarno@latimes.com