(from http://www.msnbc.msn.com/id/21376597/)

Comcast blocks some Internet traffic
Tests confirm data discrimination by number 2 U.S. service provider

By Peter Svensson

Updated: 1 hour, 26 minutes ago
NEW YORK - Comcast Corp. actively interferes with attempts by some of its
high-speed Internet subscribers to share files online, a move that runs
counter to the tradition of treating all types of Net traffic equally.

The interference, which The Associated Press confirmed through nationwide
tests, is the most drastic example yet of data discrimination by a U.S.
Internet service provider. It involves company computers masquerading as
those of its users.

If widely applied by other ISPs, the technology Comcast is using would be a
crippling blow to the BitTorrent, eDonkey and Gnutella file-sharing
networks. While these are mainly known as sources of copyright music,
software and movies, BitTorrent in particular is emerging as a legitimate
tool for quickly disseminating legal content.

The principle of equal treatment of traffic, called "Net Neutrality" by
proponents, is not enshrined in law but supported by some regulations. Most
of the debate around the issue has centered on tentative plans, now
postponed, by large Internet carriers to offer preferential treatment of
traffic from certain content providers for a fee.
Comcast's interference, on the other hand, appears to be an aggressive way
of managing its network to keep file-sharing traffic from swallowing too
much bandwidth and affecting the Internet speeds of other subscribers.

Number two provider
Comcast, the nation's largest cable TV operator and No. 2 Internet provider,
would not specifically address the practice, but spokesman Charlie Douglas
confirmed that it uses sophisticated methods to keep Net connections running

"Comcast does not block access to any applications, including BitTorrent,"
he said.

Douglas would not specify what the company means by "access" _ Comcast
subscribers can download BitTorrent files without hindrance. Only uploads of
complete files are blocked or delayed by the company, as indicated by AP

But with "peer-to-peer" technology, users exchange files with each other,
and one person's upload is another's download. That means Comcast's blocking
of certain uploads has repercussions in the global network of file sharers.