About this fork
I think the BitMessage concept is interesting and worth attention. However, I think that the current codebase will give a lot of experienced Python developers a visceral "yuck!" reaction: global variables, functions and methods hundreds of lines long, variable names hundreds of characters long, no docstrings, no package structure, etc, etc. This is not just an aesthetic thing. If the code is scary, it will be hard to attract talented crypto folks to do a proper security audit to build confidence in the system. Also, the current written documentation for the protocol is a little vague on some details, so for now the reference implementation's code is the protocol specification. As such, it needs to be easy to read.
This fork is aimed, for now, at restructuring and rewriting the BM code to improve readability and clarity. As a nice side-effect, I'll learn more about the protocol, and maybe squish some bugs along the way.
Bitmessage is a P2P communications protocol used to send encrypted messages to another person or to many subscribers. It is decentralized and trustless, meaning that you need-not inherently trust any entities like root certificate authorities. It uses strong authentication, which means that the sender of a message cannot be spoofed, and it aims to hide "non-content" data, like the sender and receiver of messages, from passive eavesdroppers like those running warrantless wiretapping programs.
Development
Bitmessage is a collaborative project. You are welcome to submit pull requests although if you plan to put a non-trivial amount of work into coding new features, it is recommended that you first solicit feedback on the DevTalk pseudo-mailing list: BM-2D9QKN4teYRvoq2fyzpiftPh9WP9qggtzh