While the use of a multipane browser is not in itself new, the operations available on it, slicing, sorting, swapping, adding, subtracting, detail view at each element for each category, is.
These types of manipulations can be described in a formal way so that they can be implemented over any organized space - whether that space organized by a database schema or a Semantic Web ontology: we've used both types of back ends.
An example of a database driven mSpace, and more detail about the functions is described in the paper mSpace: interaction design for user-determined, adaptable domain exploration in hypermedia.
An example of a functioning Semantic-Web driven, limited mspace (does not currently support swapping) can be tried at the CS AKTive Space site.
The application, which won the Semantic Web Challenge 2003, is described in IEEE Intelligent Systems. A video of CS AKTive space in action (16.6megs) is also available. We also have done an mSpace informed "AKTive Space" for exploring the photo archives of a conference, and associating those photos with related references to the conference schedule (see video).
The logical description of an mSpace is available in the following draft report (comments welcome) which also provides a tentative mapping to OWL-based Semantic Web concepts. This model approach informs the current mSpace Framework software
A comparison of mSpaces in terms of other hyperstructures such as polyarchies and zzstructures is also available (figure of 2*2*2 mSpace polyarchy shown left, from paper).
This paper, which won " ACM Special Research Distinction Awarded for Excellent Presentation of Theoretical Concepts" at Hypertext04, describes mspaces in terms of graph theory, showing mSpaces to be a special class of polyarchy. .