A few films with gossip driving the plot:

The Children's Hour
People Will Talk (1951)
The Crucible (gossip of a sort)
Johnny Belinda
Peyton Place
The Women
The Blue Angel
Sense and Sensibility
Pride & Prejudice
Persuasion
Rear Window
Rebecca
Affair of the Necklace
The Breakfast Club

Dogville seems like a likely candidate although I haven't seen it

Movies with gossip columnists/reporters as characters:
La Dolce Vita
The Cat's Meow
Beloved Infidel
Sweet Smell of Success
Roman Holiday

If memory serves, also possibly these:
Grand Illusion
Miracle of Morgan's Creek
Gigi
The Graduate
Cat on a Hot Tin Roof
Streetcar Named Desire
The Informer
The Last Picture Show
The Letter
Picnic at Hanging Rock
Wild Things
Mrs. Brown
The Birds

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