Grafana 3.0 Beta introduces significant updates and new features, such as plugin support, a reimagined UI, and enhanced personalization options, while also launching a preview of Grafana.net, a platform for discovering and managing Grafana plugins and instances. The update emphasizes extensibility through a revamped plugin SDK/API, allowing for new panels, dashboards, and app bundles, and introduces the grafana-cli tool for easy plugin installation. The UI enhancements improve both aesthetics and usability, with a modernized side menu and layout consistency across pages, while improved annotation features and updates to popular data sources like Prometheus and InfluxDB enhance functionality. Despite the absence of the highly anticipated alerting feature, which was postponed to focus on extensibility and reducing technical debt, the release promises improved code maintainability using modern technologies like ES6 and Typescript, and ensures compatibility with previous versions, albeit with some necessary updates for custom data sources and templates.