I think its might be a curiosity for need breed of SEO guys to know a lot on link farming. Well, this is old methods to get page rank for your website. Well, it’s not working anymore. This technique for bringing page rank to your website may not work now.
For doing link farming you need to make a community first those who have well page rank and can ready to exchange their link with you. The number of link you exchanges with different sites increases the number of vote come in your account. This technique is so simple to do if you have a lot of websites who ready to change their link with you.