document: Are web users really Markovian ? User modeling on the Web has rested on the fundamental assumption of Markovian behavior -- a user 's next action depends only on her current state , and not the history leading up to the current state . This forms the underpinning of PageRank web ranking , as well as a number of techniques for targeting advertising to users . In this work we examine the validity of this assumption , using data from a number of Web settings . Our main result invokes statistical order estimation tests for Markov chains to establish that Web users are not , in fact , Markovian . We study the extent to which the Markovian assumption is invalid , and derive a number of avenues for further research .
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