The main objective of Google’ s Page Rank computation is to weigh webpage popularity in the internet. It ’s concept is like you are suggesting or voting to other website by placing their link in your own webpage. If this was done naturally with your own will without others telling you to do so or for something in return, the objective is attainable and we can hope for a good search engine ranking and results.
However, many SEO and webmasters nowadays found a loop hole to take advantage of the Page Rank computation and thereby gaining high position in the Search Results. Aside from link buying, another popular way of increasing number of links or “votes” and thereby increasing pagerank is by joining link exchange programs. One of the popular link exchange program is Linkmarket.Net. Using this kind of schemes, you can gain pagerank in accordance with the formula of computing pagerank. However, the concept of obtaining page rank by “Naturally” gaining votes from other website is not anymore taking control of the quality of search results and page rank because one website can gain votes for something in return. It’s like you are buying a vote just to win in the election.
The main problem here is not to eliminate websites that participate on link exchange programs but to qualify which of them participate in such scheme and “pay them for their effort”.
I think, the best way to regain the efficiency of page rank technology in ranking websites in search results is to impose a higher pagerank decrease to a website that link to other site and to impose a lower pagerank increase to website the receives the “vote”. In that way, link exchange and link buying will no more work since it’s like killing your own website if you still join in such scheme. Moreover, if you really want to link to other website, you are willing to decrease your own page rank for them. Thus, what will left in the network are those who link in a natural way.