What is Page Jacking ?
 

Page Jacking is a black Hat technique that is used for Search Engine Index Spamming. In this technique one webmaster steal the content of high authority site and used it on his site to boost the rankings in less time.
However the more experienced pagejackers use pretty advanced techniques to get what they want; more visitors. The simply use a serverside coding language like PHP, JSP, ASP etc to detect is a search engine spider (using the user agent information) is visiting their webpage. If so they show the pagejacked content. If a regular visitor visits their webpage they simply redirect to other content. This usually isn’t useful information, but rather some landing page that persuades visitors to buy products.