The present invention is a method for improving delivery of content to a client communicating with a server on the Web. Groups or clusters of clients are formed by processing the IP addresses of the clients according to a network-aware, radix-encoded trie classification process. The groups of clients are categorized based on information about one or more clients in each group that can be determined by the server. That information is used to help drive tailored actions on the part of Web servers. Users with poor connectivity may choose not to spend much time at a Web site if it takes a long time to receive a page, even if the Web server at the site is not the bottleneck. Retaining such clients may be of interest to a Web site. Better-connected clients may be able to receive enhanced representations of Web pages such as with higher quality images. Once a group of clients is characterized as poor, a variety of server actions can be taken by the server, including altering the delivered content or the manner in which content is delivered, including guiding server policy decisions, aiding in caching decisions and deciding when to redirect the client to a mirror site. Clustering permits those actions to be taken even if no client-specific categorization is available.