A revolutionary tool that changed the world. Do not reinstall it.

Because there was no central indexing server, the creators of Kazaa argued they had no direct control over what was being shared. Multisource Downloading:

Kazaa allowed users to download different segments of the same file from multiple users simultaneously, vastly increasing download speeds at a time when broadband was just becoming common.

Kazaa was free to users but monetized through aggressive adware and spyware bundling. The software installed third-party programs (e.g., Cydoor, TopSearch) that tracked user behavior and displayed pop-up ads. This was legal but widely criticized as malicious. The parent company, Sharman Networks, also collected licensing fees from other companies that used the FastTrack protocol.