Abstract: A client receives a notification of a user interaction with an information item and creates a record describing this interaction. The client encrypts the record using an encryption key associated with a server. The encrypted record is then communicated to at least one proxy, which in turn forwards the encrypted record to a server. Upon receiving the encrypted record from the proxy, a server decrypts the record using a decryption key and analyzes the decrypted record to identify the information item and the type of user interaction. This information may be used individually or in aggregate for tracking user interests, billing advertisers or information item providers, and/or collecting anonymous information from users.