  In this paper we present a number of measures that compare rankings of search
engine results. We apply these measures to five queries that were monitored
daily for two periods of about 21 days each. Rankings of the different search
engines (Google, Yahoo and Teoma for text searches and Google, Yahoo and
Picsearch for image searches) are compared on a daily basis, in addition to
longitudinal comparisons of the same engine for the same query over time. The
results and rankings of the two periods are compared as well.
