Shane Green, a D.C.-area technology entrepreneur, self-made millionaire and advocate of Internet privacy, died March 13 at a hospital in the District. He was 49.

The cause was bile duct cancer, said a friend and colleague, Josh Galper.

Mr. Green was recognized on Washingtonian magazine’s listings of “tech titans” and was “one of the leading lights and pioneers in digital space,” Brookings Institution senior fellow and national security specialist Fiona Hill wrote in an email. A former business partner, Julian Ranger, called him an enthusiastic advocate of “the need for individuals to own and control their own data” on the Internet.

Mr. Green’s first major enterprise, started in 1999, was an online interactive mapping business that became known as the Map Network. Cities, events and venues — among them the Super Bowl, the Republican and Democratic national conventions, the NBA All-Star Game, and the Smithsonian Institution — used the company’s services. The digital navigation giant Navteq bought the business for $37.5 million in 2006.

Three years later, Mr. Green created, an online vault to store personal data such as telephone numbers, passwords, bank accounts and food recipes — and keep it safe from marketers prowling for personal data on consumers. “The real magic,” Mr. Green told The Washington Post in 2011, is “information on what you plan to do or purchase, which is the altar on which all things digital worships.”

He merged with the British company in 2017 and became chief executive of its U.S.-based operation.

Then in 2018, Mr. Green co-founded another company, Universal Basic Data Income, as a way to level the playing field with market researchers who track consumers’ online movements. UBDI, as it was called, aims to help compensate people for contributing personal data anonymously into aggregate pools that could be useful to marketers and advertisers.

Billions of dollars of advertising are based on such data. Mr. Green wanted to get some of that money into the hands of online users who created the data. “We’re trying to build a way for everyone to participate in the economics of their data,” Mr. Green told USA Today last year.

Robert Shane Green was born in Jacksonville, Fla., on Oct. 5, 1970. His father was the founder of Georgia Solar Utilities, and his mother was an insurance agent. He graduated from the University of Michigan in 1992, then attended business school at the University of Chicago for a year.

Mr. Green began his career in Washington at the Carnegie Endowment for International Peace, where his work included helping start-up businesses. Later, he specialized in underground mapping and imaging for Witten Technologies.

Survivors include his wife of 18 years, Viviana Lopez Green, and their three children, Gabriela, Javier and Emilia, all of Somerset, Md.; his parents, Robert and Janice Green, and a grandmother, Ruth Watt, all of Macon, Ga.; and a sister.

He was a sailor, a tennis player and a bicyclist, especially along the Chesapeake & Ohio Canal. Friends said he was an incurable optimist. A meal he liked was always “the best I ever had.” A good day was “the best day of my life.”