The first strike by Hollywood writers in 20 years began Nov. 5 with picket lines set up coast to coast. The strike has already disrupted soap operas, talk shows, and, more important, the flow of advertising money into network coffers.

Jay Leno was filmed talking with strikers at NBC’s Burbank, Calif., studios shortly after he was told by network executives that his services were not needed because his show was immediately going into re-runs. A spokesman at CBS said “The Late Show with David Letterman” has also been switched into re-run mode.

Fans who showed up for the “Ellen” talk show at the NBC lot in Burbank were turned away and told that taping has been put off indefinitely. Comedy Central said “The Daily Show with Jon Stewart” and “The Colbert Report” were now in re-run mode, too.

The strike by the Writers Guild of America began after the networks, during talks on Nov. 4, refused to negotiate satisfactory methods to pay writers for material that ends up on the Internet.

At Paramount Studio’s landmark gate on Hollywood’s Melrose Avenue, 50 striking writers wore red strike T-shirts. Drivers passing by honked their horns in support.

In front of NBC studios at Rockefeller Center in New York, strikers displayed a giant, inflated rat to symbolize network executives and chanted “no contract, no shows.”

The position of the networks and the studios is that the Internet is too new a media for them to be able to structure a system of compensation for the writers. In answer, Jose Arroyo, a writer for “Late Night with Conan O’Brien,” said, “Then give us a percentage, so that if they make money, we make money.”

The writers are part of an extremely volatile industry. Without meaningful job security, they depend on residual payments, which payment for any of their material used on the Internet would be, to handle many of their financial needs. Diana Son, a writer for “Law and Order: Criminal Intent,” has three children. She told The Associated Press that getting residuals was the only way she could take time off after giving birth.

Talks began in July and continued after the contract expired Oct. 31. Negotiators met Nov. 4 for 11 hours before East Coast members of the writers union announced that the strike had begun for their 4,000 members. The union even withdrew a proposal to increase the share writers get from the sale of DVDs. The proposal had been a stumbling block for producers.

The producers are resisting the writers’ insistence on pay for parts of their work used on the Internet and, in an attack on the union, the Alliance of Motion Picture Industries said, “Writers are not willing to compromise on major issues.”

In Los Angeles, writers are picketing 14 studio locations in four-hour shifts from 9 a.m. until 5 p.m. each day until a new contract is agreed upon.

The powerful Hollywood Teamsters local is leaving the issue of honoring picket lines up to individual drivers. If the drivers honor the lines, the studios will suffer much more severe economic damage and therefore more pressure to settle. Local 399, which represents truck drivers, also represents casting directors and location managers. As a union, therefore, it has legal obligations to honor contracts with producers.

The Teamsters have said publicly, however, that the clause does not apply to individuals, who are protected by federal law from employer retribution if they decide to honor picket lines.

This battle has big implications for the entertainment industry. Whatever gains are won by the writers will be demanded also by actors and directors, whose contracts expire next June.