Google Vanquished a Rival in Prague. Payback Could Hurt.

“We are an example of the consequences,” said Michal Feix, a former chief executive of Seznam, who now leads its policy and legal work as an outside consultant. Without the new laws, he said, “you just can’t compete.”

Google said its success in the Czech Republic was the result of building a superior service. Czechs “choose our products because they help people find the information they’re looking for — and because we make thousands of improvements every year,” Google said in a statement.

In the Czech Republic, Seznam’s history traces to early enthusiasm about the internet.

Ivo Lukacovic, the founder and owner of Seznam, recalled a childhood without much money; his family had no car or color TV. As a teenager in 1989, when the country was still part of Czechoslovakia, he joined classmates in mass demonstrations, known as the Velvet Revolution, that contributed to the fall of the ruling Communist Party.

“The regime collapsed, and the era of economic freedom began,” Mr. Lukacovic said on a recent blustery morning outside Prague. “Since I played with computers, I went to university,” he added.

At 22, Mr. Lukacovic dropped out of Czech Technical University in Prague after creating Seznam, which means “list” in Czech. It started as a recommendation site of 10 or so Czech websites to visit. A search engine was added in 1998; email, maps and other services arrived in the years after.

The company continued to grow after Google opened in the country in 2006. Seznam’s search engine was tailored to Czech speakers, and it added services like unlimited email storage to keep up with Google’s offerings. In 2008, the Czech Republic, whose population of 10.5 million is about the size of North Carolina, was the only place in the 31-country European Economic Area where Google was not the leading search engine.

By 2010, Seznam’s position began to change. Google had invested considerably in improving its non-English language services and tried to endear itself to Czech citizens through efforts like digitizing the ancient books held at the 18th-century Baroque library in Prague’s Old Town.