An internet traffic monitoring method, comprising: a network service provider (220.1, 220.2) analyzing a web content request from an internet user client (211.1 - 212.N) for web content from the internet, wherein the internet user client (211.1 - 212.N) has a connection to the internet through the network service provider (220.1, 220.2); the network service provider (220.1, 220.2) intercepting the requested web content and customizing the requested web content, wherein the customized web content includes the requested web content which has been modified by the network service provider (220.1, 220.2) to include at least a first monitoring implement (520.1 - 520.N) configured to forward at least one user parameter to a first advertisement selection service (240.1 - 240.N), and at least a second monitoring implement (521.1 - 521.N) configured to forward at least one user parameter to a second advertisement selection service; and the network service provider (220.1, 220.2) forwarding the customized web content to the internet user client (211.1 - 212.N) for causing the internet user client (211.1 - 212.N) to forward at least one user parameter to the first advertisement selection service (240.1 - 240.N) based on the first monitoring implement (520.1 - 520.N) and for causing the internet user client (211.1 - 212.N) to forward at least one user parameter to the second advertisement selection service based on the second monitoring implement (521.1 - 521.N); wherein the first advertisement selection service (240.1 - 240.N) selects targeted advertising web content for presentation to the internet user client (211.1 - 212.N) based on at least one user parameter received by the first advertisement selection service (240.1 - 240.N) from a monitoring implement (520.1 - 520.N, 521.1 - 521.N) of another network service provider (220.1, 220.2) in response to a separate web content request. a network service provider (220.1, 220.2) analyzing a web content request from an internet user client (211.1 - 212.N) for web content from the internet, wherein the internet user client (211.1 - 212.N) has a connection to the internet through the network service provider (220.1, 220.2); the network service provider (220.1, 220.2) intercepting the requested web content and customizing the requested web content, wherein the customized web content includes the requested web content which has been modified by the network service provider (220.1, 220.2) to include at least a first monitoring implement (520.1 - 520.N) configured to forward at least one user parameter to a first advertisement selection service (240.1 - 240.N), and at least a second monitoring implement (521.1 - 521.N) configured to forward at least one user parameter to a second advertisement selection service; and the network service provider (220.1, 220.2) forwarding the customized web content to the internet user client (211.1 - 212.N) for causing the internet user client (211.1 - 212.N) to forward at least one user parameter to the first advertisement selection service (240.1 - 240.N) based on the first monitoring implement (520.1 - 520.N) and for causing the internet user client (211.1 - 212.N) to forward at least one user parameter to the second advertisement selection service based on the second monitoring implement (521.1 - 521.N); wherein the first advertisement selection service (240.1 - 240.N) selects targeted advertising web content for presentation to the internet user client (211.1 - 212.N) based on at least one user parameter received by the first advertisement selection service (240.1 - 240.N) from a monitoring implement (520.1 - 520.N, 521.1 - 521.N) of another network service provider (220.1, 220.2) in response to a separate web content request.