After nearly four years of spinning its proverbial wheels trying to deploy a municipal Wi-Fi network, the city of Boston has settled for a patchwork of hotspots to deliver free or low-cost high-speed wireless technology to its citizens.

The latest effort was unveiled this week at Roxbury Community College, where FreeFi Networks announced the launch of an upgraded advertiser-supported Wi-Fi service. The service is a partnership with Microsoft, Hewlett Packard, and a Web-based college recruiting platform called Experience.com.

The FreeFi Networks installation follows the launch of another hotspot, powered by BelAir Networks, that was formally switched on as of March 31.

Boston joins a long list of large cities that have tried to deploy citywide municipal Wi-Fi networks, only to pull back when they struggled to gain traction. Early efforts in San Francisco and Sacramento, Calif., failed, for instance, and other attempts in Portland, Ore., and Tempe, Ariz., have been sharply curtailed.

At the same time, however, hotspots -- many of them free -- have popped up in public libraries and coffee ships throughout Boston. McDonald's and Starbucks, for instance, have both announced plans to offer free service to their patrons.

The Boston plan, which sought an infusion of $20 million, called for private and business donors to pony up funds to build the wireless network, a backhaul system, and fiber cabling for dozens of buildings in the city. The nonprofit Boston Foundation, noting that several million dollars had been raised in past years to provide computer services for the city's schools, offered to assist in raising money for a citywide Wi-Fi deployment.

The BelAir installation, serving parts of the Dorchester and Roxbury neighborhoods in the city, utilized mesh gear that the company has successfully used to deploy large networks in Minneapolis, Minn., Toronto, London, and hundreds of smaller areas. In an interview last week, BelAir CTO Stephen Raymont noted that the entire city of Minneapolis has been covered with a municipal Wi-Fi network covering 57 square miles.

However, Wi-Fi being Wi-Fi, there are some gaps in coverage and the Minneapolis network deployment initially has some areas -- as much as 10% of the covered area -- that can't be served. The Minneapolis network got a boost from the city government when it agreed to help support the network rollout, because it also offered 4.9-GHz public safety access.

Boston's longtime Byzantine politics may also have played a role in the failure of the city to roll out a citywide municipal Wi-Fi network. City council member John Tobin, rumored to be a future mayoral candidate, spearheaded the Wi-Fi effort from its beginnings four years ago, but Mayor Thomas Menino, who also has backed plans for the network, later left Tobin off the committee that was promoting the network.

The FreeFi Networks hotspot at Roxbury Community College has been established not just as a prototype for Boston, but also as a model with implications for other college sites. Part of a pilot partnership with Microsoft to evaluate ubiquitous Internet access in education settings, the effort gives students the opportunity to develop hands-on skills for technology careers.

"FreeFi Networks is helping to close this (digital) divide by providing its services to students that may otherwise not have access," said Terrence A. Gomes, president of the college, in a statement.