> but if a competitor comes out and wants to use your core, they now have to publish source for all their add-ons, so you can have them for free. 1. Strictly s

> but if a competitor comes out and wants to use your core, they now have to publish source for all their add-ons, so you can have them for free. 1. Strictly speaking, they don't have to publish anything, they have to provide the source code under the GPL to their customers/users. 2. They probably will make those addons GPL-only, so, if you want to incorprate them into your product, you have to make all your addons GPL as well.