Abstract: A user interaction analysis system receives real-time clickstream information units from a plurality of web servers and web sessions. Each information unit is associated with a single session. The analysis system uses session identifying information that is stored in a database to process the information units, to determine context values pertaining to one particular web session, and to determine that the particular web session has terminated. Upon determining that the particular web session has terminated, the analysis system generates a per-session data unit (PSDU) for that session. Each PSDU comprises click-stream information for a plurality of clicks, as well as context values, that pertain to the particular web session. The analysis system categorizes the PSDUs into a plurality of theme buckets and performs rule-based searches on the PSDUs in the buckets to identify PSDUs that meet certain search criteria. A report containing information about the identified PSDUs is generated.