A discussion at WebmasterWorld has users trying to determine why some PDF files don't get indexed with a "View as HTML" link whereas others do. How can you implement the same functionality?
Nobody knows if it's possible. The suspicion is that Google can process some PDF files and not others, and it's not an opt-out procedure.
I think it may not be displayed when Google actually has a hard time converting the PDF document to HTML, not because the webmaster instructed them to.
Meanwhile, a number of users are pretty disappointed that a webmaster would even want to disallow that link. They seem to hate the idea of having to open a file as a pure PDF.
If you want to publish documents on the web, put them in a web format.
Better yet would be an option to integrate a Google PDF reader instead of relying on Adobe's service, which is getting a lot of negative comments in the thread.
Maybe now Google have an online documents service, they could 'invent' a new pdf-style service.
Is there a directive that will allow this to be implemented? Nobody seems to know. Do you?
Forum discussion continues at WebmasterWorld.