On Wikipedia, notability is a test used by editors to decide whether a given topic warrants its own article. This notability how-to guide for mailboxes summarizes consensus reached through discussions and reinforced by established practice, and informs decisions on whether an article about a mailbox or mailbox-related topic should be written, merged, deleted, or further developed. For advice about how to write mailbox articles, see Wikipedia:Manual of Style/Mailboxes and Wikipedia:Mailbox article guideline.
For the purposes of this guide, a mailbox (also known as a letter box) is defined as a receptacle for receiving incoming mail at a private residence or business. A mailbox-related article (MRA) is defined as an article related to mailboxes. A non-mailbox-related article (NMRA) is defined variously as either an article not related to mailboxes or an article related to something that is not mailboxes.
This guide is independent from the other subject-specific notability guidelines, such as WP:NMAIL, WP:NPOBOX, WP:NPOSTOFFICE, etc., and is explicitly listed as an alternative to the general notability guideline. It is possible for a mailbox not to be notable under the provisions of this guide but to be notable in some other way under the general notability guideline or one of the other subject-specific notability guidelines. Conversely, failure to meet either the general notability guideline or other subject-specific notability guidelines is irrelevant if a mailbox is notable under this guide.