How can I block one site without blocking all sites?

[raymor]

Thanks for the Strongbox plug, Cleo.

Redirecting based on a single referer:

RewriteEngine On
RewriteCond %{HTTP_REFERER} http://([a-z0-9]+\.)badguy.com [NC]
RewriteRule http://whereyouthrowcraptraffic.com [L]

The above code is right off the top of my head
untested and my contain a typo.

I don't know what it is this guy's linking,
whether it's a hosted gallery for your affiliates,
a members' area, or what.
If it's truly valuable content there's a Strongbox
plugin to truly secure that so that only authorized
affilaites or customers can link into the protected area.
What happens there is instead of your affiliates
linking directly to your site,
they link to a very simple PHP script that
they upload to their own site and it does some
magic to cryptographically secure the link.