Spam link architectures used for search engine traffic

Today, I was reading a few articles and I came across this: spam link architecture

I can attest to the fact that I had noticed the same architecture being used by many scammers and spammers alike. Most of the architectures that was shown in the article are for search engine traffic alone.

Google recognizes 301 redirects made on your site as a way to let them know that you want to direct the flow of page rank from that original page to the newly redirected page. Most hackers take advantage of this fact and it's hardly ever noticeable to its users. That's because the 301 redirect is only used for Google bots that come to the page. They check the user agent and even the IP address to identify it as a Google bot, and if it is, it does a 301 redirect to their hacked page, which in Google's eyes, means that you are moving your content over to another domain and most of page rank to that original page should be transferred over to the hacked page. This eventually leads to higher positions on search engines. Of course, until the administrator of the original site realizes that he's no longer getting traffic from search engines and starts to get suspicious.