This is an auxiliary template that allows one to encode "|" (pipe or en:vertical bar) within template parameters. If it is unnecessary to get a "|", it is better to use "|". However the "|" delimiter for a Wiki table has to be escaped by a template if it is used within a template.

There is no such problem with "!" (exclamation mark). This problem only affects "|" (vertical bar) in conjunction with the m:Help:Parameter default mechanism within tables.

This is a high risk template.

This template cannot be substituted (it doesn't make sense).