The controversial technology, which ArsTechnica says is lincesed from PerfTech, lets the ISP insert its own content in web pages served by a third party (like Google).
In this case, Rogers displayed a warning to the customer saying that he/she has nearly reached his monthly limit.
However, as mentioned by Lauren Weinstein who first came up with the story, this could open the way for more sinister practices: ISPs could start serving adverts for example.
This could be a test case for ISPs and Content providers. Rogers has indeed modified Google's content - its homepage - without first asking the search company.
And the logical follow up to this, adds Weinstein is, "Will Web service providers such as Google and many others, who have spent vast resources in both talent and treasure creating and maintaining their services' appearances and quality, be willing to stand still while any ISP intercepts and modifies their traffic in such a manner?"