A private OID should be obtained for a company when:

Companies do not 'run out of public OIDs'; public OIDs are structured hierarchically, and a company would be assigned a specific branch, not a limited number.

Using LDAP for commercial purposes does not inherently require a private OID; a private OID is needed for custom schema definitions, regardless of commercial or non-commercial use.

Making a directory public on the World Wide Web does not necessitate a private OID unless custom schema elements are being introduced that need unique identification.

Companies obtain a private OID (Object Identifier) primarily when they plan to create custom schema files for their LDAP directory. OIDs are globally unique identifiers used to define new object classes, attributes, or syntaxes within the LDAP schema without conflicting with existing or future standard definitions. Assigning a unique OID ensures that custom schema elements are uniquely identifiable across different directories and implementations.