Winchester, MA Request a Copy functionality was added to DSpace 4.0 to facilitate access in those cases when uploaded content cannot be openly shared after submission into DSpace during an allowable embargo period. Request a Copy gives users an efficient way to request access to the original submitter, who can approve access with the click of a button. This practice complies with most applicable policies as the submitter interacts directly with the requester on a case by case basis.
About embargo periods
From the SPARC Europe web site: "An embargo period means the period of the time upon official publication that the article is not openly accessible yet.
Publishers ask for publication embargoes to build in sustainability for their business.
Most funders and institutions that mandate or recommend their grant receipients to make their articles available in Open Access, respect these publisher’s policies and mention these in their Open Access Clauses." 
Any DSpace Institutional Repositories using version 4.0 may implement Request a Copy functionality to maximize open access to research during OA embargo periods.
 SPARC Europe web page: http://sparceurope.org/embargoes/