1. A method implemented by one or more servers coupled to a network, for dynamically adjusting sample rates of variables relating to attention by users to a webpage, the webpage displayed on a plurality of user devices concurrently connected, by the network, to a website displaying the webpage, the method comprising: designating, by at least one server, a desired sample rate by determining one or more statistical characteristics of aggregated data derived from gathering sample data relating to attention by each of a plurality of users to online content on the webpage, wherein the online content is at least one of text, picture and video; monitoring, by at least one server, aggregated data flows from the plurality of user devices to determine if current new information for particular online content is required for statistical accuracy, wherein the monitoring is at least in part by a sample data collection script placed in the plurality of user devices; assessing the impact of the aggregated data flows, by at least one server, on a downstream analytic server; and adjusting the aggregated data flows, by at least one server, by changing sample rate parameters for measurement scripts provided to the plurality of user devices.