In the Netmail Archive administration console you have two agents that seem to do a similar task: put data to a new location. This article will expand on the difference between the Export job and the ILM Groom job.
An Export job was intended to copy data to another location or in another format; for example to create a backup, or for creating a test location, or to provide to an external party, etc.
The ILM Groom was designed to move data from one repository to another; for example to groom ex-employee data into a "Departed" location, or to move archives older than 3 years into long-term storage, etc.
So the difference lies in whether you wish to have the original data removed or not from the source location.