In this keynote presentation, titled "The Asset Pipeline and Our Postmodern Hybrid JavaScript Future," delivered by David Heinemeier Hansson at RailsConf 2011, the focus is primarily on the new features introduced in Rails 3.1, particularly the Asset Pipeline. This feature is designed to enhance how developers manage assets like JavaScript, CSS, and images within their Rails applications, addressing long-standing frustrations with asset organization.

Key points discussed in the presentation include:
- The Motivation for the Asset Pipeline: Hansson emphasizes that the motivation for improvements in Rails often stems from identifying pain points in development. He highlights the clutter that arises from unsystematic organization of JavaScript files, comparing it to a messy junk drawer that becomes hard to work with over time.
- Grouping and Organization: The presentation emphasizes the importance of organizing files in logical groupings rather than clustering them chaotically. Hansson proposes the idea of a rule where directories should ideally house no more than 13 files, reinforcing a tidy organizational structure.
- Improvements over Previous Methods: With Rails 3.1, the Asset Pipeline replaces the earlier approach that involved a single large JavaScript file with a more structured method of organizing assets into three main categories: application-specific assets, library assets, and vendor assets, which significantly reduces clutter.
- Centralized Dependency Management: The presentation illustrates how the Asset Pipeline allows for better dependency management using tools like Bundler, enabling smooth handling of JavaScript and stylesheets without manual intervention.
- Introduction of CoffeeScript: Hansson concludes by discussing CoffeeScript, a more user-friendly syntax for JavaScript that allows for cleaner and more maintainable code, ultimately enhancing the developer experience.

In conclusion, Hansson asserts that the Asset Pipeline not only provides a much-needed solution to asset organization challenges but also encourages developers to create cleaner and more enjoyable coding experiences. The separation and management of assets along with the introduction of CoffeeScript signal a significant step towards a more cohesive and efficient Rails development environment.