1. An internet traffic monitoring method, comprising: a network service provider analyzing an HTTP transaction involving an internet user client and web content from the internet, wherein the internet user client has a connection to the internet through the network service provider; the network service provider responding to the HTTP transaction by forwarding, to the internet user client, a modified web object including at least a first monitoring implement associated with a first advertisement selection service for causing the internet user client to forward at least one user parameter to the first advertisement selection service and including at least a second monitoring implement associated with a second advertisement selection service for causing the internet user client to forward at least one user parameter to the second advertisement selection service; and after forwarding the modified web object to the internet user client, the network service provider forwarding an embedded web object, originally associated with the HTTP transaction, to the internet user client; wherein the first advertisement selection service selects targeted advertising web content for presentation to the internet user client based on the at least one user parameter forwarded based on the first monitoring implement included in the modified web object forwarded by the network service provider, and based on at least one user parameter from a monitoring implement included in a modified web object forwarded by another network service provider in response to a separate HTTP transaction.