I know that's an old post, but whatever. Being open source only means the code belongs to the community as a whole. There will be ways to allow only the official build on the servers. If 55 people make their own versions, they should instead commit the changes to the official build, which would get reviewed before being released as 'official', and there we go: 55 new features or bugs fixed, easy as pie. That doesn't stop someone from making its own wacky client, but that's just part of the fun, as long as the servers can detect them. An open source client means we also need an open source server and biller. We already have ASSS for server, and several billers exist as well. Open source means you need extra precaution against hacks, but it also means you can answer quickly to a new hack, if the protection is broken.