A comprehensive analysis of social media platform Bluesky provides insights into its structure, polarization and political leanings, in a new study published in open-access journal PLOS One on February 26, 2025, by Dorian Quelle and Alexandre Bovet, from the University of Zurich, Switzerland.
Many social media platforms rely on proprietary algorithms to recommend content, a methodology that has received increasing backlash over the years. However, Bluesky instead allows users the ability to curate their experiences. The authors of the present study analyzed the social media site's trajectory from its invite-only launch in February 2023 to the 5.7 million users hosted in May 2024, examining its network structure, polarization, and political leanings of its users.
Despite Bluesky's unique structure, the researchers found that the user interactions on Bluesky are similar to those of many other platforms, in that a few highly active users dominate the landscape.
The researchers tracked spikes in user sign ups, which often correlated with news related to X (formerly known as Twitter). For example, X's current owner Elon Musk announced in September 2023 that X would require users to pay a fee, and Bluesky saw its highest number of new users over the next two days. The second largest spike in new Bluesky users they observed happened in July 2023 when X users experienced a bug interrupting their access to the platform.
These reactions demonstrate that many X users see Bluesky as the closest alternative. However, Bluesky appears to be relatively left-leaning: of links shared by Bluesky users, over 60% led to left-leaning websites. Centrist sources made up about 20% of links shared, and only about 8% of links led to right-leaning websites.
Despite this political alignment, the researchers found that Bluesky users particularly diverged on the topic of the Israel-Palestine conflict. Using a machine learning algorithm to categorize relevant posts as pro-Israel or pro-Palestine, the researchers found that prior to the October 7 attacks on Israel and the subsequent retaliation, most posts about Israel-Palestine relations were neutral. Afterwards, there was a sharp split between users, with a greater number of posts skewing more pro-Palestine over time.
Given its similarities to larger social media sites, Bluesky offers a unique opportunity to study how these networks grow from their beginnings and change over time. The polarization around the Israel-Palestine conflict also demonstrates that divisions can occur even in networks that are otherwise politically aligned, and future research could probe these splits.
The authors add: "Our study shows the potential of open social media platforms for investigating the impact of their design and algorithms on collective human behavior."
In your coverage, please use this URL to provide access to the freely available article in PLOS One: https://plos.io/3QgOno6
Citation: Quelle D, Bovet A (2025) Bluesky: Network topology, polarization, and algorithmic curation. PLoS ONE 20(2): e0318034. https://doi.org/10.1371/journal.pone.0318034
Author countries: Switzerland
Funding: The author(s) received no specific funding for this work.
