\section{GPLv3~\S7(e): Peer-to-Peer Sharing Networks}

% FIXME: rewrite a bit, maybe drop reference to bitorrent?

Certain decentralized forms of peer-to-peer file sharing present a challenge

to the unidirectional view of distribution that is implicit in GPLv2 and

Draft 1 of GPLv3.  It is neither straightforward nor reasonable to identify

an upstream/downstream link in BitTorrent distribution; such distribution is

multidirectional, cooperative and anonymous.  In systems like BitTorrent,

participants act both as transmitters and recipients of blocks of a

particular file, but they see themselves as users and receivers, and not as

distributors in any conventional sense.  At any given moment of time, most

peers will not have the complete file.

% FIXME: rewrite a bit.

The GPL permits distribution of a work in object code form over a network,

provided that the distributor offers equivalent access to copy the

Corresponding Source Code ``in the same way through the same place.''  This

wording might be interpreted to permit BitTorrent distribution of binaries if

they are packaged together with the source code, but this impractical, for at

least two reasons. First, even if the source code is packaged with the

binary, it will only be available to a non-seeding peer at the end of the

distribution process, but the peer will already have been providing parts of

the binary to others in the network, functioning rather like a router or a

cache proxy.  Second, in practice BitTorrent and similar peer-to-peer forms

of transmission have been less suitable means for distributing source code.

In large distributions, packaging source code with the binary may result in a

substantial increase in file size and transmission time.  Source code

packages themselves tend not to be transmitted through BitTorrent owing to

reduced demand. There generally will be too few participants downloading the

same source package at the same time to enable effective seeding and

distribution.

% FIXME: rewrite a bit.

We have made two changes that recognize and facilitate distribution of

covered works in object code form using BitTorrent or similar peer-to-peer

methods.  First, under new subsection 6e, if a licensee conveys such a work

using peer-to-peer transmission, that licensee is in compliance with section

6 so long as the licensee knows, and informs other peers where, the object

code and its Corresponding Source are publicly available at no charge under

subsection 6d.  The Corresponding Source therefore need not be provided

through the peer-to-peer system that was used for providing the binary.

Second, we have revised section 9 to make clear that ancillary propagation of

a covered work that occurs as part of the process of peer-to-peer file

transmission does not require acceptance, just as mere receipt and execution

of the Program does not require acceptance.  Such ancillary propagation is

permitted without limitation or further obligation.