There are 2 Metadata Item Parameters that can be used on any Metadata Item; Format and BlankFormat. The purpose of these parameters is to allow you to define content that will be used only when the Metadata Item yields a value (Format) or when the Metadata Item does not yield a value (BlankFormat).

These 2 parameters are used extensively, particularly the Format parameter, as they allow you to define surrounding content that will only be used if there is actual content for output. For example, the See Also section present in most Page Types only outputs the "See Also" header if there are actually See Also items to output.

BlankFormat is particularly useful for output within table cells; some browsers render completely empty table cells without a border, so the BlankFormat parameter allows a space to be output if there is no content produced by the Metadata Item in order to avoid this problem. It could also be used to explicitly indicate there is no content - e.g. blankformat="(No content defined - coming soon!)".