A method for tracking an activity of a user, the method includes: downloading, over a network, web page content that comprises a tracking code; tracking, at least partially by executing the tracking code by a user computer, user activities that are responsive to at least a portion of the downloaded web page content, wherein the tracking comprises generating user activity information; compressing and buffering a portion of the user activity information; and transmitting to a tracking entity, at least a compressed portion of the user activity information when a first transmission criterion is fulfilled.