Just for clarification... according to Product Submission Guidelines.
Can I sell the product from my own site?
No, we currently are only allowing developers to sell products through our online store. Your customers will pay through ArrowChat.com and you will be paid regularly. This eliminates the hassle of you having to build your own site and trying to advertise it.
Now, as we are able to upload our own themes, modifications, or applications for ArrowChat but not permitted to sell them on our website. That is fair, your software, your code, your rules.
However, I am developing notifications for JomSocial. In doing so, the ONLY files being modified are ONLY within the core folders of JOMSOCIAL and are licensed under GNU/GPL. This requires NO modification or addition to any directory/file related directly to ArrowChat.
Therefore selling these "modifications" on my own site is NOT something you can restrict, because ArrowChat does not have the authority to govern another software package's files nor go against the right everyone is given to expand upon GPL'd software.
I have written this post for clarity's sake, and to avoid any unnecessary future issues or potential restriction of my own distribution or forum privileges here from the staff at ArrowChat.