Abstract
The acquisition of Twitter by Elon Musk has spurred controversy and
uncertainty among Twitter users. The move raised as many praises as concerns,
particularly regarding Musk's views on free speech. As a result, a large number
of Twitter users have looked for alternatives to Twitter. Mastodon, a
decentralized micro-blogging social network, has attracted the attention of
many users and the general media. In this paper, we track and analyze the
migration of 136,009 users from Twitter to Mastodon. Our analysis sheds light
on the user-driven pressure towards centralization in a decentralized ecosystem
and identifies the strong influence of the social network in platform
migration. We also characterize the activity of migrated users on both Twitter
and Mastodon.