Private blog networks (PBNs) help individuals with building backlinks to their website that earns money for them, typically an e-commerce or affiliate website. Google does not condone PBNs, however, as long as each blog appears to uniquely owned, they cannot determine if the blog is part of a network.
To pass on link juice, PBN blogs should never link to each other, only the money site. Obviously, using different domain registrars and blogging platforms is essential, as does creating the blogs at different times. Free hosts make this easier, although a person would need to use paid hosting services as well.
While PBNs may help some webmasters who are struggling, it is vital to have perfect on-page SEO and numerous social signals, which are both white hat strategies, before attempting gray hat tactics. A webmaster who keeps creating new, engaging and link-worthy content on the money website's on-site blog will do better that someone who participates in a PBN scheme. Earned links always provide more link juice that guest posts or other unearned links. White hat SEO tactics are a long term solution for driving traffic to a website, while the webmaster using gray or black hat tricks will always wonder if today will be the day he or she incurs a penalty from Google.
Additionally, SEO takes time to show results. Each strategy takes about six months to offer any noticeable results. This is why webmasters of money websites turn to AdWords for their initial traffic.