Metadata is information about the document. This information is stored within the document itself; for example who created it, who edited it, what were the changes made, who else worked on it. Metadata has the potential to embarrass or negatively impact a company's financial well-being. Recent high profile incidents in the UK and at the United Nations prove the point.
A document security utility (also known as a data leakage prevention tool) will mitigate the risks associated with unwanted, potentially embarrassing metadata, being sent to clients. These tools provide users with a high level of confidence that sensitive documents sent to clients and third parties are manually or automatically "cleansed" of harmful metadata when being e-mailed outside of the company.