Decentralized alternatives like Mastodon and Lemmy are gaining popularity in response to growing complaints about centralized social media platforms such as Twitter and Reddit, which frequently prioritize business interests over user experience. This study employs a mixed-methods approach to scrutinize the impact of Reddit users’ migration on Lemmy. It elucidates user growth patterns, revealing significant registration spikes and centralization trends within decentralized structures. A sentiment analysis with VADER, incorporating a dataset of 48,272 comments from before and after the migration, depicts a predominantly positive sentiment towards Lemmy and criticisms of Reddit. A comprehensive survey with 354 responses from major Lemmy communities validates and supplements the findings, shedding light on users’ motivations, adaptation experiences, and long-term intentions. Furthermore, qualitative interviews with 16 purposively sampled users offer in-depth insights into individual experiences, community dynamics, and perspectives on decentralization and engagement. This study reveals a promising future for Lemmy, highlighting its adaptability and users’ commitment, and contributes valuable insights to the discourse on the sustainability and growth of decentralized platforms in a dynamic digital landscape.