14. A system comprising: a computer processor configured for: receiving a first document and a second document, the second document comprising a count of words less than or equal to a count of words in the first document; generating a frequency distribution for the words in the first document and a frequency distribution for the words in the second document; determining an intersection of the first document and the second document, the intersection comprising a set of words that appear in both the first document and the second document; for each word in the intersection, comparing the frequency of the word in the first document with the frequency of the word in the second document; for each word in the intersection, selecting the lower frequency between the frequency of the word in the first document and the frequency of the word in the second document; and determining a similarity measure between the first document and the second document as a function of a count of the words in the intersection, a count of the words in the second document, the selected lower frequencies, and the frequency distribution for the words in the second document; comprising a computer processor configured for: (a) computing a first ratio of the count of words in the intersection to the count of words in the second document, and multiplying the first ratio by a count weight; (b) computing a first sum of the lower frequencies, computing a second sum of the frequency distribution of the second document, computing a second ratio of the first sum to the second sum, and multiplying the second ratio by a word score weight; (c) computing a resultant sum of step (a) and step (b); and (d) dividing the resultant sum by a sum of the count weight and the word score weight.
14. A system comprising: a computer processor configured for: receiving a first document and a second document, the second document comprising a count of words less than or equal to a count of words in the first document; generating a frequency distribution for the words in the first document and a frequency distribution for the words in the second document; determining an intersection of the first document and the second document, the intersection comprising a set of words that appear in both the first document and the second document; for each word in the intersection, comparing the frequency of the word in the first document with the frequency of the word in the second document; for each word in the intersection, selecting the lower frequency between the frequency of the word in the first document and the frequency of the word in the second document; and determining a similarity measure between the first document and the second document as a function of a count of the words in the intersection, a count of the words in the second document, the selected lower frequencies, and the frequency distribution for the words in the second document; comprising a computer processor configured for: (a) computing a first ratio of the count of words in the intersection to the count of words in the second document, and multiplying the first ratio by a count weight; (b) computing a first sum of the lower frequencies, computing a second sum of the frequency distribution of the second document, computing a second ratio of the first sum to the second sum, and multiplying the second ratio by a word score weight; (c) computing a resultant sum of step (a) and step (b); and (d) dividing the resultant sum by a sum of the count weight and the word score weight. 15. The system of claim 14 , comprising a computer processor configured for comparing a word in the intersection against a file of words, and removing the word from the intersection when the word appears in the file of words.