M3A: Model, MetaModel and Anomaly Detection for Inter-arrivals of Web Searches and Postings

'Alice' is submitting one web search per five minutes, for three hours in a row-is it normal? How to detect abnormal searchbehaviors, among Alice and other users? Is there any distinct pattern in Alice's (or other users') search behavior? We studied what is probably the largest, publicly available, query log, containing more than 30 million queries from 0.6 million users. In this paper, we present a novel, user-and group-level framework, M3A: Model, MetaModel and Anomaly detection. For each user, we discover and explain a surprising, bi-modal pattern of the inter-arrival time (IAT) of landed queries (queries with user click-through). Specifically, the model Camel-Logis proposed to describe such an IAT distribution; we then notice the correlations among its parameters at the group level. Thus, we further propose the metamodel Meta-Click, to capture and explain the two-dimensional, heavy-tail distribution of the parameters. Combining Camel-Log and Meta-Click, the proposed M3A has the following strongpoints: (1) the accurate modeling of marginal IAT distribution, (2) quantitative interpretations, (3) anomaly detection, and (4) generality-being able to explain multiple datasets.