-If it was by selection, is it a permanent selection till something happens to the user or a temporary selection that is done periodically?
To my understanding i think it is a decision to be made by the Admin in choosing a desired qualification for a moderator, secondly if it is by appointment then an individual may be lucky to have won the interest of the admin having enough quality and professional works ethics before been considered. If it were to be by election then individual have to sit down in building a credible qualifying profile and which has to be evident even on the forum.
for instance one must be a quality poster, experienced in managerial skills, have knowledge in dealing with data, good moral conduct, have customers service experience because you will be dealing with large numbers of forum members, be consistent, ability to multitask, ability to judge right and know how to make report.