Here's an excerpt from the press release:
Portico and the Koninklijke Bibliotheek, the National Library of the Netherlands (the KB), are pleased to announce they have reached an agreement for an off-line copy of the Portico archive, which exceeds 6 million articles and 60 million files, to be held for safekeeping by the KB. Through its e-Depot program the KB has demonstrated its role in the vanguard of digital preservation. Placing a Portico-owned copy of the archive, in a secure access- and climate-controlled facility operated by the KB is one component of the replication strategy Portico is implementing to ensure the safety and security of the archive upon which a growing, international community relies. This arrangement also illustrates one way in which organizations internationally recognized for their digital preservation obligations and expertise can cooperate to form a strong, supportive network to safely preserve digital materials.
Here's a description of e-Depot from its home page:
The e-Depot is a digital archiving environment that ensures long-term access to digital objects which would otherwise be threatened by rapidly evolving software and hardware platforms as well as media decay. It is the dedicated archiving environment for the KB’s national electronic deposit collection. In addition, it will include the Dutch web archive and digitised master images. In line with the international nature of information provision, the KB has extended its e-Depot services to publishers worldwide. The e-Depot is supported by sustained research and development efforts geared towards maintaining the integrity of stored digital objects.
Here's a description of Portico from its "About Portico" page:
Portico began as the Electronic-Archiving Initiative launched by JSTOR in 2002 with a grant from The Andrew W. Mellon Foundation to build upon The Foundation's seminal E-Journal Archiving Program. The charge of the Electronic-Archiving Initiative was to build a sustainable electronic-archiving model, and for more than two years, project staff worked on the development of necessary technology and engaged in extensive discussions with publishers and libraries to craft an approach that balances the needs of publishers and libraries while generating sufficient funding for the archive. In 2004, the Electronic-Archiving Initiative became a part of Ithaka Harbors, Inc., a non-profit organization with a mission to accelerate the productive uses of information technologies for the benefit of higher education around the world. Building upon extensive input gathered from commercial and not-for-profit publishers and guidance offered from libraries at a range of small, medium and large academic libraries, an electronic archiving service, known as Portico, was developed. Portico was launched in 2005 with additional support from JSTOR, Ithaka, The Library of Congress, and The Andrew W. Mellon Foundation.