What is page hijacking?

[NolanBrian]

I think page hijacking is a form of search engine index spamming. It is achieved by creating a rogue copy of a popular website which shows contents similar to the original to a web crawler, but redirects web surfers to unrelated or malicious websites. Spammers can use this technique to achieve high rankings in result pages for certain key words

[jamsen]

Page hijacking is a technical form of redirecting Web traffic that exploits certain glitches in search engines.

[blessy_smith]

Page hijacking is creating a copy of a popular website that shows contents that is similar to the original. This technique can be used by the spammers to achieve higher rankings for some of the keywords.

[Manov]

Page hijacking is a form of search engine index spamming. It is achieved by creating a rogue copy of a popular website which shows contents similar to the original to a web crawler, but redirects web surfers to separate, unrelated or malicious websites. Spammers can use this technique to achieve high rankings in result pages for certain key words.

Page hijacking is a form of cloaking, made possible because some web crawlers detect duplicates while indexing web pages. If two pages have the same content, only one of the URLs will be kept. A spammer will try to ensure that the rogue website is the one shown on the result pages.

In some cases, legitimate web pages can be edited by external advertisers via XSS and redirected to promoting web site.

[alok897]

Page hijacking is a method of cloaking a webpages prevent to show duplicate content on search engine in this method if you have a two pages with same content only one of the page will be indexed. This method used by spammer to be prevent penalty from search engine and ranking high on their.

[sabrinasai]

Here is a clean explanation on that, you can go through it!
http://www.loriswebs.com/hijacking_web_pages.html