Spaces are a new way in Octopus to organize projects, environments, and permissions that improves on project groups. Spaces allow organizations to separate resources and access by team, application, hosting location, or other logical grouping. This provides benefits like limiting visibility and permissions to only relevant resources, preventing accidental deployments to the wrong systems, and making the interface less cluttered with many projects and environments. The document discusses how different organizations like Octopus itself, banks, software companies, and small startups could use spaces to better structure their deployment processes.