An old ISP-Planet article about the ACLU report on Broadband Regulation (I couldn't find the actual report unfortunately) says:

The ACLU report says, "a company providing Internet access over a cable system has many opportunities for interfering with online activities, often in ways that are invisible to their customers. In fact, much like the administrator of an office LAN, they have the potential for an all-seeing, all-controlling power over the activities of customers on their networks. Cable providers are under no obligation to remain a neutral pipe for content over an end-to-end—and have many incentives for interfering with that pipe."

...

"In short, cable broadband providers have both the financial incentive and the technological capability to interfere with the Internet as a free and neutral medium for the exchange of information," the report states.

Well, I was hit by this very issue. Not in a hard way, almost unnoticeable. Frankly, if I didn't try to use VS.NET to directly work with my C# project on my host site, but instead I worked locally and used FrontPage to sync the two sites, I wouldn't have noticed this.

The issue is that Ygnition is stripping down HTTP headers from the packets I receive. In this particular case, it's the WWW-Authenticate header, which VS.NET needs to get in response to start the authorization process with the remote server.

In a time period of six months I bugged my broadband provider Ygnition (former Interquest) to resolve this issue. Ultimately, after months of silence, I was told on the phone that “The HTTP header is stripped down. This is the way Ygnition infrastructure works and  we can't [i.e. won't] do anything about it.”

I haven't checked what other scenarios/applications might be blocked by Ygnition, but I wouldn't be surprised if there are other as well. I also don't think this was a explicit management decision; it's more of a case of lazy and incompetent technical staff that can't configure their “infrastructure” correctly. But it comes to show how easy for your provider is to prevent you from using certain application.

I don't think it'll be too long before some marketing guy at your ISP decides that this might a good way to “encourage“ you to buy their IM software. Or that you should be getting your information only from them.

And you won't have any choice, because “this is the way their infrastructure works”...