Frequency list searches offer you the ability to compare the rate of use of words. It is most interesting when you enter a wildcard pattern (e.g. raison*) or a list of words. Bibliographic meta data constraints are supported. Here's a sample for that hooks up the Bibionet collection: http://philologic.uchicago.edu/philologic3/bibliopolis.frequencylists.html
For example, if you wanted to compare the use of amour and haine in a certain collection of texts, enter those terms in the search box and run the query (here's an example from Biblionet: http://philologic.uchicago.edu/cgi-bin/philologic3/wordfreqgen.pl?dbname=bibliopolis&author=&title=&date=&genre=&word=amour+haine
Clearly, love triumphs over hate. But what about in Victor Hugo's work? Add 'Hugo' to the Author field and re-run the query: http://philologic.uchicago.edu/cgi-bin/philologic3/wordfreqgen.pl?dbname=bibliopolis&author=hugo&title=&date=&genre=&word=amour+haine
Frequnecy list searching capability is not included by default when building a database, and must be run afterwards (See Development:Loading).