Information may be fragmented by physical location or devices. In the same device they may be inaccessible to other applications.Information may be disperse on a number of sources, such as calendars, emails, files web sites etc.
They survey different Unification strategies by PIM. Unification strategies in PIM chooses some lowest common denominator of information to be unified, ignoring many particulars of the data in each applications.The table summarize them.
They describe approaches to unification that differe from the ones proposing to expand email client.
The Universal Labeler includes modules that works as add-ons and extension to other applications. It has a module, the Project Planner that allows the uses to build and outline by dragging resources in. It resembles an outline, with the possibility to add links and notes.A guiding principle of UL is that information management and task project management represent two sides of the same coin. UL allows people to work on a project top down or bottom up buy creating an outline and then dragging items or by gathering info first. Over time a plan emerges where heading are folders and hyperlinks are shortcuts. The planner has a rich-text document-like feature.
Haystack creates a uniform namespace for referring to all individual information objects. For example people are data types that appears in a variety of PIM (email, author in a juke box). Haystacks uses RDF to give each information an unique identifying name. In haystack data model, a typical application file is shredded into many individual information objects of various type that are connected through application-specific relationships. Each document has a web-like navigation paradigm: by clicking on the author you can navigate to a view of the author.
Disclaimer: these summaries are made to help me remember the content and the main ideas of the paper. Since I am interested in certain aspects, I may leave out others. My comments focus on my particular point of view.