Point taken, Mr2001. At least with regards to email, I think my point still stands though.
I am only aware of two different “spam-blocking” strategies employed by ISPs. One strategy, such as Earthlink’s SPAMINATOR, allows users to subscribe to the service. It doesn’t filter the spam at the edge of the network, indeed, it uses application content filtering technology to simply sort the spam and hold it available for review. And it is entirely optional, at the users discretion.
The other strategy is using a spam black-hole list, such as the MAPS Realtime Blackhole List. This list IS network level filtering, and not application level filtering. That is, all traffic from servers acting as sources of spam are blocked. These servers are acting as open relays, which do not allow the verfication of the sender’s email address. The Internet community considers these “misconfigured” devices, and blackhole ALL traffic from them, including otherwise legitimate traffic. It is non-discriminatory, and once the server is properly configured, it can be removed from the blackhole list.
Really, the issue is the same with forged packet sources. As you point out yourself, it is not filtering based on content, it is network level filtering. And that is done by every clueful Internet operator (that’s part of running the network).
But it is VERY different from application level, or content, filtering.
Unfortunately, it is even less likely to be effective than these other approaches have been in stopping spam or cleaning up Usenet.
Finally, ISPs may block and/or disable any of their customers that violate their Acceptable Use Policy “AUP” (which typically include a prohibition on Unsolicited Bulk Commercial Email, as well as violation of standard Usenet posting guidelines, such as cross-posting).
But there is no claim that the RIAA site has violated any AUP or any laws. IWT has simply made a political statement, under the guise of being a “good network citizen”. It’s a crock. Personally, I don’t want my ISP censoring the (legal) content available to me. I also don’t want my ISP to become an activist in the digital rights controversy.
Don’t get me wrong, if the RIAA was using their site to tamper with users files (without legal authority), they should be blackholed by every responsible provider.