Short answer
No sign of it. After the 2016 referendum, posts mentioning Brexit or the UK rose to about 9% of posts on party and leader pages in 19 other European countries, but equally for Eurosceptic and other pages, and Eurosceptic pages drew no extra engagement relative to their rivals.
What the evidence shows
- The study compares 37 Eurosceptic pages, classified with the PopuList, with other pages in the same country and week in a 25-week window around the vote (42,265 posts from 143 pages).
- Engagement per post with Eurosceptic pages did not change differentially in the two weeks after the vote (−0.02 log points, SE 0.11), nor did the mix of reactions.
- Eurosceptic pages posted about 16% less than other pages in those weeks, but similar dips appear in late June 2014, 2017 and 2018.
- Of five later Brexit milestones, only the March 2019 extension gave a clearly positive estimate, about 23%.
- In the United Kingdom itself, interactions per post with all parties' pages roughly doubled relative to pages elsewhere.
Caveats
The March 2019 estimate does not survive clustering by country or adjustment for testing both outcomes, coincides with the European Parliament campaign, and came without more posts about Brexit.