Web 1.0 focused on commerce while Web 2.0 emphasizes user participation and contribution. The concept of Web 2.0 emerged from a 2004 brainstorming session between O'Reilly and MediaLive International. Key principles of Web 2.0 include customization for individual users, harnessing collective intelligence by allowing users to add value through tagging, reviewing and editing, and specialized databases to store user-generated content and power applications. Web 2.0 applications are also characterized by perpetual beta releases and an emphasis on services over single-use software.