Flattening the and news: Platformisation the erosion of topical diversity across news outlet types

This article examines how platformisation reshapes topical diversity across news outlet types in Norway. Using Latent Dirichlet Allocation (LDA) topic modelling and diversity indices on more than 220,000 articles from 22 national, regional, local and niche outlets, it compares content published on proprietary websites with that on Facebook, Instagram and TikTok. The findings reveal a ‘flattening’ of the news agenda on social media. While distinctions between news outlet types remain clear online, they largely disappear on social media, where engagement-driven logics promote soft topics. The effect is strongest for local outlets, whose civic and community-oriented reporting gives way to sports, human interest and entertainment news. Ownership explains little once editorial type is considered. The study demonstrates how platformisation erodes local journalism’s distinctiveness and challenges media policies designed to safeguard diversity and democratic pluralism in the digital public sphere.