Cloaking
It is called "cloaking" when the webmaster shows different pages to the search engine and the user. True cloaking is somewhat rare, but spammers do use other methods to show different pages to search engines than to users. Two such techniques used by spammers are:
JavaScript redirects
100% frame
Spammers use JavaScript redirects to show one page to search engines while sending users to a different page. Looking at the page first with JavaScript enabled and then with JavaScript disabled reveals the differences.
Webmasters sometimes cloak what users see by using frames. Two frames (pages) exist, but one frame takes up 100% of the screen. The user sees one frame (page), but the search engine sees both frames. Here are instructions for looking at the different frames in Firefox:
Viewing Frame Information in Firefox
• Right-click on the page.
• Click "This Frame."
• Click "View Frame Info."
• Compare the URL of the frame with the URL of the page. If they are different, the page is probably 100% framed, and should be considered spam.
