Worldwide

DDEX messages make use of two-letter ISO territory codes. This allows a label to state that a Release may be used in, say the “DACH” countries:

<TerritoryCode>DE</TerritoryCode>
<TerritoryCode>AT</TerritoryCode>
<TerritoryCode>CH</TerritoryCode>

It also allows to say that a deal is available everywhere but in the DACH countries:

<ExcludedTerritoryCode>DE</ExcludedTerritoryCode>
<ExcludedTerritoryCode>AT</ExcludedTerritoryCode>
<ExcludedTerritoryCode>CH</ExcludedTerritoryCode>

The latter XML snipped has the semantic of "World-wide, less Germany, Austria, Switzerland". .

To avoid this pitfall, the label should limit its Deals to the territories it would want the DSP to make the Release available in.

DSP expanding its territorial reach

If a label sends a DSP, who operates in only one territory a Deal with

<TerritoryCode>
  Worldwide
</TerritoryCode>

and the DSP subsequently choses to branch out its operation into a second territory, the Deal would allow the DSP to make the relevant Release available in both territories.

For a list of valid ISO Territory Codes please refer to Wikipedia for details.