The new 'Kissinger Cables', dating from 1973 to 1976, have already led to a number of front page stories around the world and were previously available through the US national archives, although not as easily accessible, Julian Assange told a press conference today.
The files were "technically in the public domain," said Julian Assange, speaking via video link to the press conference in Washington, "but not practically available in a way that the public would be able to make sense of."
He also described the database as "the single most significant geopolitical publication that has ever existed."
The project, which has been a year in the making, was presented by Assange and Wikileaks spokesperson Kristinn Hrafnsson as a reaction to the process of "reclassification" of initially declassified documents.
"We are doing what the government should be doing in making this easily accessible to everyone," said Hrafnsson, describing a "very serious trend of reclassification that has been shrouded in secrecy."
Hrafnsson detailed how in 2006 it was revealed that more than 55,000 documents that had previously been declassified were reclassified under the demands of the CIA.
"It is a very serious situation when the administration tries to hide documents that were previously available," said Hrafnsson. "You might be tempted to say that the government cannot be trusted with these documents, so we took it into our own hands in making this available in a very accessible database where you can easily search for stories that are very significant."
A number of news organisations from around the world have been quick to find stories using PlusD, despite the Kissinger-era documents only being available since Sunday 8 April.
"This is what Google should be like," said Assange, "this is a search system that investigative journalists can use effectively."
Hrafnsson told Journalism.co.uk that although it will take time for more stories to emerge from this current set of new data there is scope for further expansion in the future.
"This is a database that can be expanded and we'll certainly be looking into the possibility of getting access to more documents that can be merged with this as it's important to have these archives in an accessible format," he said.