High PR Backlinks are said to be the holy grail of SEO which propels websites higher up the rankings in Google search results for competitive keywords. Private blog networks are coming to be known as the heart of such high PR backlinks.
Private blog networks are nothing but a network of blogs each having a high Pagerank (above 2) and all of them are owned by a single individual or a company. SEO hosting plans are used to host these private blogs. Each blog will have a unique C-class IP. The nameservers and whois details of these blogs are all hidden from public. Hence, it will not be possible to discover the network. Backlinks from such high PR private blog networks would go a long way in helping your website rise in search engine rankings.