1. A method of presenting data from a hierarchical data source, said method comprising the steps of: (i) constructing a first view of the hierarchical data source; (ii) obtaining an occurrence probability of at least one context data from at least the first view of the hierarchical data source; (iii) identifying a compulsory entity in the first view; (iv) selecting a context entity from the first view and the context data based on the occurrence probability; and (v) presenting a hierarchical data structure, wherein the hierarchical data structure is a subset of the hierarchical data source, comprising a plurality of context data, wherein each of the plurality of context data corresponds to the identified compulsory entity and the selected context entity, wherein the hierarchical data structure is assigned a score equal to an occurrence probability of an ancestor node of the compulsory entity given the occurrence probability of the context data associated with the compulsory entity, and the context entity is selected from the group consisting of: (a) the ancestor node; (b) a first set of nodes along a directed path in the hierarchical data source from the ancestor node to the compulsory entity; (c) a second set of nodes selected from a descendent node of the ancestor node in the first view, each of the second set of nodes being selected based on a corresponding occurrence probability, said occurrence probability being derived from the occurrence probability of the ancestor node; (d) a third set of nodes selected from a descendent node of the ancestor node in the first view based on a corresponding distance from each of the third set of nodes to the ancestor node in the first view; and (e) a fourth set of nodes selected from a descendent node of the ancestor node in the first view based on a corresponding distance from each of the fourth set of nodes to the compulsory entity in the first view.
1. A method of presenting data from a hierarchical data source, said method comprising the steps of: (i) constructing a first view of the hierarchical data source; (ii) obtaining an occurrence probability of at least one context data from at least the first view of the hierarchical data source; (iii) identifying a compulsory entity in the first view; (iv) selecting a context entity from the first view and the context data based on the occurrence probability; and (v) presenting a hierarchical data structure, wherein the hierarchical data structure is a subset of the hierarchical data source, comprising a plurality of context data, wherein each of the plurality of context data corresponds to the identified compulsory entity and the selected context entity, wherein the hierarchical data structure is assigned a score equal to an occurrence probability of an ancestor node of the compulsory entity given the occurrence probability of the context data associated with the compulsory entity, and the context entity is selected from the group consisting of: (a) the ancestor node; (b) a first set of nodes along a directed path in the hierarchical data source from the ancestor node to the compulsory entity; (c) a second set of nodes selected from a descendent node of the ancestor node in the first view, each of the second set of nodes being selected based on a corresponding occurrence probability, said occurrence probability being derived from the occurrence probability of the ancestor node; (d) a third set of nodes selected from a descendent node of the ancestor node in the first view based on a corresponding distance from each of the third set of nodes to the ancestor node in the first view; and (e) a fourth set of nodes selected from a descendent node of the ancestor node in the first view based on a corresponding distance from each of the fourth set of nodes to the compulsory entity in the first view. 16. A method according to claim 1 wherein said first view of the hierarchical data source comprises a tree representation and step (i) or (iii) includes detecting a user's selection of a sub-tree of said first view, and wherein, (iv) comprises selecting a child node of a parent node in said user-selected sub-tree, said selecting comprising the steps of: (iv-a) computing a first occurrence probability of said parent node appearing without any of its child nodes given the occurrence probability of said parent node, and the ancestor node of said user-selected sub-tree; if said first occurrence probability is less than or equal to 0.5 (iv-b) computing a second occurrence probability of each of said child node of said parent node given the occurrence probability of said parent node, and the ancestor of said user-selected sub-tree; (iv-c) computing a total sum of said second occurrence probability of all child nodes of said parent node; and (iv-d) selecting the context entity from the set of all child nodes of said parent node in order of descending values of said second occurrence probability until the sum of said second occurrence probability of selected nodes equals or exceeds half of said total sum.