In this paper, we undertake a large-scale study of online user behavior based on search and toolbar logs. We propose a new CCS taxonomy of pageviews consisting of Content (news, portals, games, verticals, multimedia), Communication (email, social networking, forums, blogs, chat), and Search (Web search, item search, multimedia search). We show that roughly half of all pageviews online are content, one-third are communications, and the remaining one-sixth are search. We then give further breakdowns to characterize the pageviews within each high-level category.
We then study the extent to which pages of certain types are revisited by the same user over time, and the mechanisms by which users move from page to page, within and across hosts, and within and across page types. We consider robust schemes for assigning responsibility for a pageview to ancestors along the chain of referrals. We show that mail, news, and social networking pageviews are insular in nature, appearing primarily in homogeneous sessions of one type. Search pageviews, on the other hand, appear on the path to a disproportionate number of pageviews, but cannot be viewed as the principal mechanism by which those pageviews were reached.
Finally, we study the burstiness of pageviews associated with a URL, and show that by and large, online browsing behavior is not significantly affected by "breaking" material with non-uniform visit frequency.