Short answer
Not mainly. Engagement was concentrated, but not extremely: it is better described as a broad base with a moderate head than as a market of hits.
What the evidence shows
- The study uses 846,289 posts from 185 party and leader pages in 20 European countries, 2010 to 2020. In the median page-year the top 1% of posts drew 8% of the interactions, the top 10% drew 36% and the bottom half 18%.
- The single most engaging post drew 2.8% in the median page-year and more than 10% in only 5% of page-years.
- Concentration was similar for parties and leaders, populist and other parties, and parties in and out of government.
- The most engaging posts were more often videos and photos, less often links, and more likely to fall in the 30 days before a national election.
Caveats
Whether good years were driven by hits is mixed: depending on how extreme swings are handled, the top tenth accounted for between 39% and 50% of the variance in changes.