San Francisco will soon roll out free public Wi-Fi down long stretches of Market Street, with plans to light up the city's main vein from the Castro district to the Ferry Building by early next year.

The city famously squandered its chance for a citywide system several years ago. But the Department of Technology, in partnership with other agencies, has been installing free Internet in patches ever since. There are now dozens of public hotspots, mostly around low-income communities, parks, hospitals and libraries.

The efforts have largely fallen under the radar, probably because stories about a block of Wi-Fi aren't as headline grabbing as a system that blankets the city. But residents, businesses and visitors are bound to notice the next installment along one of the city's most prominent commercial corridors.

San Francisco's acting Chief Information Officer Jon Walton said the network should provide adequate coverage for common Internet use.

"We want anybody walking up and down the street, sitting in the park or having a cup of coffee, to be able to hop onto the network and use it," he said.

Several years ago, Google and EarthLink agreed to provide San Francisco with free Wi-Fi service, but the plan fell apart amid political infighting, concerns about privacy and financial problems at EarthLink.

Similarly ambitious efforts have flopped around the country for some combination of political, economic or technical reasons. It turns out it's expensive and difficult to provide a Wi-Fi system that serves a large city. But Walton believes the patchwork approach, which sidesteps much of the political drama, will eventually lead to the same result. Declining prices and improving technology are also moving us ever closer to that goal.

"Free public Wi-Fi is an idea that will happen," Walton said. "It's a question of when, not if."

There is still debate about whether cities should be in the business of paying for free Wi-Fi, but there shouldn't be.

These networks are every bit as central to the information economy as roads were to the industrial one. It's how we move the products of the day. It's the basis of the communications that have become vital to our personal and professional lives.

Beyond that, public Wi-Fi offers Internet access to those who can't afford it. It nudges private Internet service providers to offer better service at lower prices. It offers alternatives when the strained cellular networks of companies like AT&T fail. And it's a competitive lure for attracting businesses and people to San Francisco.

San Francisco's network is a basic, open Wi-Fi system (users will see: SFGov_Free_WiFi). The city doesn't monitor use, block sites or require accounts.

Walton said it's no more or less secure than any open Internet signal, so users should exercise common-sense discretion about the sites they visit and information they enter (for instance, I wouldn't do my online banking over public Wi-Fi).

Walton added that the system isn't tied to the city's network, so it shouldn't raise security concerns for law enforcement and other departments.

San Francisco also plans to restore public Wi-Fi access at Union Square and add hotspots along parts of Golden Gate Park, the Mission Street corridor and additional libraries and open spaces. It chooses the locations of access points based on demand (residents can add suggestions at sfgov.org/wifi) and cost efficiency. The city has an online map of Wi-Fi sites available to the public ( www.sfgov3.org/ftp/survey/wifi_map.html). The Department of Technology secured $80,000 from the Board of Supervisors for Wi-Fi projects during this year's budget negotiations. It's been making the most of that money by, whenever possible, installing access points where the city already has power and data fiber lines, such as traffic lights or public buildings.

Walton expects the Market Street rollout to begin in December and to be completed around the end of March.

City apps: In other city tech news, the Department of Technology is on the verge of delivering mobile apps that will provide a new means of accessing the city information and services now available on SFgov.org. It built versions for both Android and Apple smart phones and is awaiting approval to appear in Apple's App Store.

"We understand people are more mobile, and if they want to access city services, we want them to be able to do it on demand," said Ron Vinson, director of media for the department.

Users of the app will be able to watch live city meetings, check out the social media feeds of various departments, and look up other city information. Planned updates will include tablet versions of the software, and the ability to submit questions or concerns to the city's 311 customer service center, Vinson said.

The city is also releasing a mobile version of the website (m.sfgov.org), as well as a new section of the home page that showcases mobile apps that it has developed or that rely on its data. That would include a compelling one unveiled this week by Assessor-Recorder and mayoral candidate Phil Ting.

The Parkzing app for Apple gadgets is designed to help people avoid the wallet-dinging frustration of having a car towed in San Francisco. If a drivers launch the app after they park, it will alert them 10 minutes before a tow zone goes into effect at that location or the night before morning street cleanings.

Rather than navigating through the usual city process for approving and developing technology, Ting and his organization, Reset San Francisco, sponsored a mobile app contest.

The winner, Aren Sandersen, developed the software in two months and snagged a $1,000 prize.

"Using Web 2.0 tools, Sunshine (Ordinance information) requests and a little old-fashioned incentive-based marketing, we were able to do in less than two months and for just $1,000 what it would have taken City Hall two years and millions of dollars to accomplish," Ting said.