Barry Schwartz has pointed to a thread at Search Engine Watch Forums where an aggrieved website owner has complained of hijacking. The owner of www.wenlockbasin.com has reported that his website just disappeared from the search results, even when searched with the domain name. The directory Hotfrogs replaced the site in the SERPs of Google.
As moderator Mcanerin explained:
Hotfrog appears to link to websites using a redirection script issuing a 302 redirect. For new/low ranking sites, this can result in what is called a "hijack".
This can happen because a 302 actually tells a search engine that the original site is HotFrog and that it has been temporarily moved to your URL. Accordingly, the search engine shows the "original" if it has enough link juice.