Modifying web pages before those get into customers hands and eyes is risky enough business. This week, two U.S. lawmakers have raised deep privacy concerns over cable service provider Charter Communication's intent on tracking its users' web traffic.

While Charter on the one hand has claimed they do not gather any information that can specifically pinpoint an individual, they have also confirmed that will alter advertisements on web pages that are more “catered” to the viewer – even though the person surfing the net could have no prior knowledge of this taking place behind the scenes.

The U.S. reps have complained with Charter making this an opt-out program, saying that a mere snippet is not enough to inform people about what is really going on. Some (perhaps many) of its users have taken some very reasonable exception to Charter's confession of Internet-usage stat gathering as a result.

The program, which has yet to launch, is one of several other such examples in which an ISP is looking to generate extra revenue by controlling what sort of sites and advertisements a customer sees. The problems that can arise as a result are plentiful, from depriving website owners of their own advertising revenue as well as not presenting an “honest” web page to a customer. With only a little abstraction, an ISP could theoretically modify any page they wish. Imagine if you were looking for an alternative provider for Internet access, only to have search queries take you nowhere except your current ISPs pages. Charter is entering some dangerous territory.