1. A programmed digital computing device implemented system for determining a quantitative measure of qualitative usability of related Web pages, comprising: a Web server to maintain related Web pages that each include at least one hyperlink referencing and proximal cues describing distal content in another such related Web page; a storage device to store an information goal comprising one or more keywords; a processor comprising: an input module configured to identify a target Web page within the Web pages; a network generation module to generate an activation network, comprising: a graphing module to build a directed graph comprising nodes corresponding to the Web pages and arcs corresponding to the hyperlinks; and a weighting module to assign a weight to each arc in the directed graph to represent a probability of traversal of the corresponding hyperlink based on a relatedness of keywords in the information goal to the proximal cues included in each of the Web pages; a simulator module to simulate user flow through the Web pages comprising: a selector module configured to select a starting node from the directed graph; a counter module to set a count of traversals; and a navigation module to navigate iteratively through the activation network for the set traversal count; a satisfaction module to compute the probability that the target Web page has been found after the traversals as a satisfaction measure, comprising: a conversion module to convert the node corresponding to the target Web page to a termination node; and a calculating module to calculate a product of the weights of the arcs along each traversal through the activation network to the node corresponding to the target Web page and to sum the product of the weights of the traversals; and an evaluation module to determine a metric as a quantitative measure of usability, comprising: a data structure module to represent the probability of traversing each such hyperlink in light of the information goal as a data structure; and a metric module to guide the traversal through the activation network based on each such probability wherein the probability is chosen from at least one of the probability having the highest value at each such node in the traversal and the probability having the best value in light of reaching the information goal at each such node in the traversal is chosen; a display to display the quantitative measure of usability, and a comparison module to compare the satisfaction measure to the quantitative measure of usability to determine an upper bound for the information goal.