The icon indicates that accessing that resource requires free membership to the site where the resource exists. In the case of Facebook groups, it indicates that the group is a Closed Group and you need to request access. The icon indicates that accessing that resource requires a paid membership to the site where the resource exists.
If you would like to add a resource to this list, please submit the information to the Add a Resource form. If you have a comment about a specific resource, you should go to the specific page for that resource (click on the comment number on the right side of the resource line) and enter a comment there.