As the blog post announcing this points out (http://m.newyorker.com/online/blogs/closeread/2013/05/introducing-strongbox-anonymous-document-sharing-tool.html ht

As the blog post announcing this points out (http://m.newyorker.com/online/blogs/closeread/2013/05/introducing-strongbox-anonymous-document-sharing-tool.html http://m.newyorker.com/online/blogs/closeread/2013/05/introd...) in a lot of ways this is an extension of the mailing address or phone number that the New Yorker has advertised (and informants have been using) since the 1920s.