Now a days some of the companies are making money and cheating clients like anything.
Now the question arises why I am saying this because, most of the link firms buying the fake domains which has pr1 to pr2 range of to pr4 and pr5 , they simply buy it make it new thematic website without caring what is its past theme. So this is ridicules this days they are only concentrating on making money by selling links from this crappy website which we used called "drop domain links".
According to me Google, Yahoo, and Bing should be strict about that fact that peopls are cheated with this crappy link building policies, which is not stable, ethical as well.

How this process is recycling:
Suppose you have a website which represents health related services of your(as you are on this field) now after some time you are not interested to carry your website any more and you sell it on the auction, then the main movie started, most of link building companies going for pr ranking domain auction, randomly they buys yours as you got a good page rank, then they will buy the domain and turn it according to there need in like then can make it even porn if they need to sell links from there, then put free template and start link building from the home page it self, after massive link building when your domain lost its page rank then they left it.
Start looking for new domains, so that way they are doing there business, if Google, Yahoo, Bing changes its algorithm to track down to this kind cheating link building services, they some common people will get some relief and they wont be cheated by this ugly manner.

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