I suspect the difference is that Google Docs and MS Office don't integrate seamlessly into your front-end product and provide your users with a collaborative ed

I suspect the difference is that Google Docs and MS Office don't integrate seamlessly into your front-end product and provide your users with a collaborative editing experience. They would have to know they're using Docs or Office (and if necessary, acquire their own account and maintain their own license in good standing, whatever that entails. Either way, the users' data is ultimately to whatever extent locked up in that solution, and not in your product.) It makes sense to me, that you can use their flagship editor product and advertise for CKeditor, as long as you're publishing your work under the same copyleft license so they don't need to feel like you've taken advantage of them for a commercial endeavor. Under a GPL license, nothing is preventing you from charging your users, but also it is probably generally expected that nothing is preventing the users from borrowing your source code, then standing up their own instance of the tool and maintaining it in-house, either. In this way, it makes sense. You can either pay CKeditor for their work when you integrate it ... or, for no money, you can commit to not use the editor to hold your users and their data hostage. (I'm over-dramatizing a bit, but also not. People regularly talk about freeing themselves from their Google Mail hostage situations, especially on HN.) Maybe $29/mo is a lot for 25 monthly active users when you're operating a business at web scale, but it's really not a lot of money for a company with 25 employees who has maybe built their own bespoke in-house collaborative solution, and managed to do it using CKeditor instead of rolling their own editor or cobbling one together from other free components. I don't know if that's the target market, but that's certainly the base case, if your start-up company is "dogfooding" its own solutions. If your users are not worth $1/mo + your other overhead costs, then maybe they don't need to get real-time collaborative editing? (Or maybe it doesn't need to come from your solution...)