Advertisements via squid

Insert ads in user-requested internet web pages. A method for insertion of advertising content in an Internet web page, located on a target web site and requested by a web client. In one embodiment, a request from the web client for the web page is intercepted and used to retrieve the web page from the target web site. HTML code on the web page is then re-written to generate a modified web page including an ad insertion code fragment. The modified web page is sent to the web client, which executes the code fragment to cause the advertising content to be displayed.