A space is a container for a project or interest: watches, library items, documents and conversations all belong to one.
Every account has a default space. Anything created without choosing a space lands there. The default space can't be deleted, but you can rename it.
Create extra spaces in the sidebar — "Competitor research", "Reading", "Job hunt". Each has a name, an icon and a description; the description helps the agent file things into the right space.
Choose a target space when creating a watch or saving a page; assistant actions (saving items, writing documents) carry a space too. Documents and items are grouped by space in the sidebar.