I have done some checking and there are a number of web sites which link directly to documents (such as pdf files I 'give away free') on my site. When I'm on one of these sites there will be a link for me to 'download' the document and it downloads the document but you're right at that site and never leave it. This is a scraper site (or whatever you call it - no original content).
Is there any way to protect against this?