A very good add-on to GPL. SaaS is nothing new but I was always wondering why it wasn't included. Remember, on old days if the systems allowed users, customers, whatever to run remote batch, time sharing, etc all software was running centralized, none ever needed outside the service provider installation. I'm a big fan of GPL because it gives everybody a way to make business, still maybe agree with Linus that external binary ( like kernel ) drivers should be allowed if there is an "user exit" but that is a minor point, the current world is complicated and there may be reasons why you just can't publish everything. Business is not the reason but patents and other forms of copyright licenses still is, unfortunately.