5. The medium as in claim 2 , wherein calculating the second ranking of terms for the second set of resources includes: for each term in each respective document in the second set of resources, calculating a relative importance value for a given term by performing the steps of: determining a frequency of occurrence value for the given term in the document; determining a group occurrence value indicative of a number of documents in the grouping of resources in which the given term occurs; and using the frequency of occurrence value and the group occurrence value to calculate the relative importance value for the given term.
2. The medium as in claim 1 , wherein the grouping of resources is a grouping of documents, the instructions, when executed by the processing device, further enabling the processing device to perform operations of: calculating a first ranking of terms for the first set of resources, the first ranking indicating a relative importance of distinctive terms contained in each document in the first set of resources; and calculating a second ranking of terms for the second set of resources, the second ranking indicating a relative importance of distinctive terms contained in each document in the second set of resources.