14. A method comprising: receiving a collection of text-based terms; analyzing groupings of consecutive text-based terms in the collection to identify occurrences of different combinations of text-based terms in the collection; based on the analyzing, creating a tree in which a first term in a given grouping of the groupings is defined as a parent node in the tree and a second term in the given grouping is defined as a child node of the parent node in the tree; and maintaining frequency information representing the occurrences of the different combinations of text-based terms in the collection.
14. A method comprising: receiving a collection of text-based terms; analyzing groupings of consecutive text-based terms in the collection to identify occurrences of different combinations of text-based terms in the collection; based on the analyzing, creating a tree in which a first term in a given grouping of the groupings is defined as a parent node in the tree and a second term in the given grouping is defined as a child node of the parent node in the tree; and maintaining frequency information representing the occurrences of the different combinations of text-based terms in the collection. 16. The method of claim 14 further comprising creating each of the groupings to include a same number of consecutive text-based terms selected from the collection; and based on the analyzing, identifying occurrences of single-word terms and multi-word terms in the ordered collection, the multi-word terms including up to as many words as indicated by a value of the same number.