Bluesky was developed as a reference implementation of the AT Protocol, an opencommunication protocol for distributed social networks.[11] Bluesky Social promotes a composable user experience and algorithmic choice as core features of Bluesky.[12][13][14] The platform offers a "marketplace of algorithms" where users can choose or create algorithmic feeds, user-managed moderation and labelling services, and user-made "starter packs" that allow users to quickly follow a large number of related accounts within a community or subculture.[15][16][17] The AT Protocol offers a domain-name–based handle system within Bluesky, allowing users to self-verify an account's legitimacy and identity by proving ownership of a domain name.[17][18]
Bluesky began in 2019 as a research initiative at Twitter, becoming an independent company in 2021.[19][20] Development for the social app accelerated in 2022 after Elon Musk's acquisition of Twitter and subsequent severing of ties between the companies.[21][22] Bluesky launched as an invite-only service in February 2023 and opened registrations in February 2024.[23] Former Twitter CEO Jack Dorsey left Bluesky Social's board by May 2024.[24] The social media platform grew after October 2024, reaching 20 million users by November 2024 and 30 million by January 2025.[25][26][27]
^ ab"Division of Corporations – Filing". Government of Delaware. Archived from the original on September 21, 2015. Retrieved January 11, 2024. File Number: 6282898, Incorporation Date: 10/4/2021 (mm/dd/yyy), Entity Name: BLUESKY SOCIAL, PBC, Entity Kind: Corporation, Entity Type: Benefit Corporation, City: WILMINGTON, County: NEW CASTLE, State: WA
^Staff writer (2025). "Bluesky Social on the App Store". apps.apple.com. Retrieved January 8, 2025. 113 Cherry St # 24821 Seattle, Washington 98104-2205 United States; Phone Number: +1 2068895601
^Jansen, Mark A. "Bluesky Social, PBC". FENWICK & WEST LLP. tsdr.uspto.gov. United States Patent and Trademark Office (USPTO). Archived from the original on July 13, 2021. Bluesky Application Serial Number #98165726,113 Cherry St, #24821 Seattle Washington 98104
^"Bluesky User Counter". www.blueskyusercount.com. Archived from the original on February 15, 2025. Retrieved February 16, 2025.
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