Why would @Waindigo be kidding? This is the model that he operates - people pay for the add-on development (both initially and then adding features) and it is then released for free to the community. It's different from the paid-for model that you operate but it works and the community benefits from it.
Thanks @Martok. Not everyone will agree with our model, but that we have never had to release a paid add-on continues to show how great the XenForo community is. We cannot show enough our appreciation to those members of the community who do contribute for the benefits of the community as a whole.
It is always difficult to ask for more contributions without making it sound like we don't appreciate the massive contribution members have already made. But we now have over 150 resources available and have no plans to stop releasing many many more.
Added permission for user to mark their own thread as solved (requires edit own post permission to also be set). Any user with the edit thread permission will also automatically have permission to mark a thread as solved.