GPL does not, cannot, and will not protect the developer who writes the original code. But that’s not why we use it.
The New York Times erected a paywall, to prevent freebie theft of their articles. Within hours, a workaround had been found. This stuff doesn’t work.
You can add your own, user defined, sortable columns to core admin panels as of WordPress 3.1, but there are limitations.
WordPress 3.1 removed them. I don’t use ’em but people kvetched so I wrote this over a ‘smoke break.’
As of WordPress 3.1, the idea of a ‘Super Admin’ menu has been replaced by ‘Network Admin’, but also gone is the concept of ‘Dashboard Blog.’