Web 2.0 refers to changes in how software and users utilize the World Wide Web, focusing on collaboration, sharing, and user-generated content through tools like social media sites, wikis, blogs, YouTube, and Google Docs. The document provides examples of helpful technology tools and subscriptions like Atomic Learning and United Streaming for teaching, as well as an overview of social bookmarking using Delicious and Google services like Gmail, Sites, and Calendar. It also outlines the library's technology training sessions on Wednesdays and resources on the library technology page.