In reply to the above modern stations are in fact not much different. However in the age of widespread internet access many stations are going offline in favor or web sites with hidden content within the html/xml/etc of the page, in the code of an ad image, etc. These are much more useful as they use less power then SW radio and can be less up for weeks on end. Pages can easily be hidden on a site if need be and instead of a one time page and second page on a different server can use the same system to hide a one time key.