1. A method implemented at a computing device having a processor, the method comprising: processing, by the processor of the computing device, a plurality of items to extract a plurality of keywords contained in the items, the processing including forming two or more of the plurality of keywords into keyword phrases, wherein the processing is performed at least in part based on a relative closeness of the plurality of keywords, one to another, the relative closeness partially defining a relevancy of one of said items to another of said items; forming a plurality of groupings of the keywords based on the relative closeness; combining the plurality of groupings to build balanced keyword hierarchies that comprise a predetermined number of balanced top-level islands, the combining comprising: organizing the plurality of groupings to create a plurality of small islands based on the relative closeness of the plurality of groupings; reducing number of the plurality of small islands to form the predetermined number of top-level hierarchical islands, the reducing comprising: combining the plurality of small islands to multiple high-level islands each having a hierarchy of a subset of the plurality of small islands, the multiple high-level islands having at least a first high-level island and a second high-level island; determining that a set of small islands to be combined to the first high-level island will cause the first high-level island to include an unbalanced number of small islands; maintaining the first high-level island balanced by moving the set of small islands to be combined to the second high-level island, wherein the second high-level island has less closeness value than the first high-level island, and repeating the combining, determining and maintaining until the predetermined number of top-level hierarchical islands are formed; outputting one or more of the predetermined number of top-level hierarchical islands for display on a display device as arranged in one or more hierarchies such that at least one of the plurality of keywords is selectable on the display device, wherein the one or more of the predetermined number of top-level hierarchical islands include the keyword phrases; receiving, from a user input via an input device, a selection of one of the plurality of keyword phrases; and navigating, at the computing device based on the selection, to a subset of the plurality of items that: are configured as emails; and include or relate to the one of the plurality of keywords.
1. A method implemented at a computing device having a processor, the method comprising: processing, by the processor of the computing device, a plurality of items to extract a plurality of keywords contained in the items, the processing including forming two or more of the plurality of keywords into keyword phrases, wherein the processing is performed at least in part based on a relative closeness of the plurality of keywords, one to another, the relative closeness partially defining a relevancy of one of said items to another of said items; forming a plurality of groupings of the keywords based on the relative closeness; combining the plurality of groupings to build balanced keyword hierarchies that comprise a predetermined number of balanced top-level islands, the combining comprising: organizing the plurality of groupings to create a plurality of small islands based on the relative closeness of the plurality of groupings; reducing number of the plurality of small islands to form the predetermined number of top-level hierarchical islands, the reducing comprising: combining the plurality of small islands to multiple high-level islands each having a hierarchy of a subset of the plurality of small islands, the multiple high-level islands having at least a first high-level island and a second high-level island; determining that a set of small islands to be combined to the first high-level island will cause the first high-level island to include an unbalanced number of small islands; maintaining the first high-level island balanced by moving the set of small islands to be combined to the second high-level island, wherein the second high-level island has less closeness value than the first high-level island, and repeating the combining, determining and maintaining until the predetermined number of top-level hierarchical islands are formed; outputting one or more of the predetermined number of top-level hierarchical islands for display on a display device as arranged in one or more hierarchies such that at least one of the plurality of keywords is selectable on the display device, wherein the one or more of the predetermined number of top-level hierarchical islands include the keyword phrases; receiving, from a user input via an input device, a selection of one of the plurality of keyword phrases; and navigating, at the computing device based on the selection, to a subset of the plurality of items that: are configured as emails; and include or relate to the one of the plurality of keywords. 7. A method as described in claim 1 , wherein a preview pane displays results of navigating a hierarchy of groupings concurrent with the navigating.