Yes. The referrer prefix (>) can be used to block pages referred from a site.

For example, >somesite.com will block all pages where the referrer is somesite.com (i.e., if you follow a link from somesite.com then the linked page will be blocked).

Note that sometimes the URL of the referrer is not passed to the linked page, in which case LeechBlock will not detect it. In other words, do not expect this feature to work 100% of the time!

If you want referred pages to be allowed rather than blocked, you should select the option Treat referrers as allow-conditions rather than block-conditions under Advanced Options. Thus, if you were to select that option with the example above, the effect would be to allow all pages linked from somesite.com. (Note that this will have an effect only if you have also specified some sites to block when the referrer condition is not met.)