1. In a system wherein a web page is accessible to a client from a server, and wherein the web page has an associated Uniform Resource Locator (URL) or link thereto corresponding to an address, wherein in response to a request for the web page the server provides the web page to the client, a method of, providing a modified web page to the client in response to a request from the client, comprising: asynchronous to, and prior to said request from the client, in dependence upon predetermined conditions, analyzing at least a portion of the requested web page with an analyzer in a computer based system to identify at least a predetermined characteristic and creating transformation instructions that will change the predetermined characteristic when the web page is modified; and storing the transformation instructions in a repository; modifying the web page provided by the server in response to the request to the web page based on transformation instructions that were stored in the repository prior to said request from the client; and, providing the modified web page to the client.