document: A large-scale analysis of query logs for assessing personalization opportunities Query logs , the patterns of activity left by millions of users , contain a wealth of information that can be mined to aid personalization . We perform a large-scale study of Yahoo ! search engine logs , tracking 1.35 million browser-cookies over a period of 6 months . We define metrics to address questions such as 1 ) How much history is available ? , 2 ) How do users ' topical interests vary , as reflected by their queries ? , and 3 ) What can we learn from user clicks ? We find that there is significantly more expected history for the user of a randomly picked query than for a randomly picked user . We show that users exhibit consistent topical interests that vary between users . We also see that user clicks indicate a variety of special interests . Our findings shed light on user activity and can inform future personalization efforts .
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