“It doesn’t end here,” Ms. McDormand said backstage after winning the best actress Oscar for her I’m-not-going-to-take-it-anymore character in “Three Billboards Outside Ebbing, Missouri.” “The whole idea of women trending? No. Not trending. African-Americans trending? No. Not trending. It changes now, and I think the inclusion rider will have something to do with that. Right? Power in rules.”

With that, she charged forth into the official Oscars after-party. “Oh my god, mac and cheese,” she said, as a waiter handed her a serving. After temporarily losing possession of her Oscar, her next stop was the Vanity Fair party, where she would commandeer an entire bucket of fried chicken. Don’t like it? Too bad.

Inclusion riders — stipulations that A-list actors can place in their film contracts that gender and ethnic diversity be reflected among cast and crew members, with studios required to pay fees for failing — represent something specific that stars can do to make sure that Time’s Up is more than a moment. Asked at the Vanity Fair event if she planned to begin demanding inclusion riders, which she said she heard about for the first time at a dinner on Friday night, Ms. McDormand replied: “Oh, yeah. Majorly. We’re not going back.”

But some Hollywood women were less optimistic.

“How many times have we felt, ‘Oh, there’s going to be change,’ only to turn the corner and be let down?” Sam Taylor-Johnson, the director of films like “Nowhere Boy” and “Fifty Shades of Grey,” said at the Vanity Fair party. In the end, however, she felt hopeful. The reason? She said her daughter, a student at Stanford University, had told her that she believed things were actually moving in a positive direction.