Thorsten Joachims has won one of three 2015 SIGKDD Test of Time Awards for his 
2002 paper, "Optimizing Search Engines using Clickthrough Data".  The citation 
reads, "The paper introduced the problem of ranking documents [with respect to] 
a query using not explicit user feedback but implicit user feedback in the form 
of clickthrough data. The author presented the Ranking SVM Algorithm to solve 
the proposed ranking problem. The paper has stimulated much follow-up research, 
and the Ranking SVM Algorithm has been widely used for many applications, as 
evidenced by the very large number of citations. The work has also been included 
in various textbooks."

The award recognizes outstanding papers from past KDD Conferences beyond the 
last decade that have had an important impact on the data mining research community.