The permission settings vary for different people. Generally, 755 for directories and 644 for files works just fine for most people, including myself. It depends on the server configuration. BoonEx has also place .htaccess files in every directory, which denies external access, so I do not see an issue even with 777 directory permissions.

Dolphin is open source and licensed under the Creative Commons. As part of this license, you have access to the source code, and permission to modify it as you see more see fit, but you cannot remove the link-backs without the payment of a license. This does not mean that the script is not open source, as open source (as said above) does not necessarily mean "free" (though the script is still free, just with the limits explained before). BoonEx is a company, and requires a source of income, which they have every right to have, and deserve to make money off their hard work. If you have a problem with this, then this is not the script for you.

You have no right to remove the link-backs directly, and you cannot claim that the script being open source will allow you to do so. Open source software can still be under a license, like most of the popular open source software, which restricts what you can and cannot do with the source code. No amount of changes to the script can warrant the removal of the link-back code. It is either you purchase a license, or you leave them be.

A wiki module has been planned by BoonEx since the beginning of Dolphin 7, and will become available some time in the future. An exact date is not yet known, but I expect it will be when Dolphin 7.1 is released, which will be the first "feature" release. I could explain how to replicate wiki functionality in one of the current modules, but I don't feel like it.

Limit reached...