Satoshi Nakamoto registered the “bitcoin” project on SourceForge.net on November 9, 2008. This was just nine days after publishing the Bitcoin whitepaper to the Cryptography Mailing List on October 31, 2008.
SourceForge served as the primary hosting platform for the Bitcoin project, providing source code version control (SVN), file release hosting, and the bitcoin-list mailing list. The project page at sourceforge.net/projects/bitcoin/ became the central hub for Bitcoin’s early development and distribution.
Every Bitcoin release from v0.1 (January 2009) through v0.3.19 (December 2010) — Satoshi’s final release — was distributed as a file from that SourceForge page — the project lived there for the whole of Satoshi’s active development.