I've never heard the term either. If it's "pdf gateway", here's a Jakob Nielsen summary from July 2003... [useit.com...]
Summary: Spare your users the misery of being dumped into PDF files without warning. Create special gateway pages that summarize the contents of big documents and guide users gently into the PDF morass.
While this was a 2003 article (so many of the bandwidth issues no longer apply and Adobe Reader is much, much faster to load now than it was then), I still hate being taken directly to a pdf file, so the idea is appealing.