The biggest issue with building a Private Blog Network is undoubtedly keeping it safe from being detected by Google.
 
Once a PBN is “discovered” by Google, it will lose its ability to pass any link juice down to the sites it is linking out to.
 
Of course, there is the standard “link echo effect” through which the link juice to sites it is already linking out to will remain active for 3 to 6 months.
 
This has been confirmed by top SEOs in the industry and is a very important insight, because you can use it to your advantage while building links – knowing that when a link or a site gets flagged or de-indexed by its ranking power to its current sites (the link juice) remains intact for a while.
 
This does not apply to building fresh backlinks – as you definitely WONT get any juice from them at all ever – and it does not help  at all if you try and build links from a site that has already been hit by Google, prior to your building backlinks from it.
 
I recently wrote a post about how you can test the power of a PBN site – so you can test the power of PBN backlinks – and if you haven’t yet read it I would highly recommend you do.
 
In this post I will go over the results of a PBN experiment conducted by some of the top SEO experts. Matt Diggity from Diggity Marketing conducted and experiment and shared some very interesting results. Full credit to Yashar Ghaffarloo and Matt Diggity for this and many of the discoveries that I talk about here. If you want an elaborate breakdown of their experiment you can read about it here. However, for most of you this is not necessary as I’ve summarized the jargon and results in this easy to understand post.
 
For an in-depth overview on Private Blog Networks, make sure to check out the highly popular and shared, 85+ page guide and blog post I wrote on how to build a pbn.
 

Quality of Hosting Is Important

Does substandard hosting play a key role in making a PBN toxic and opening it up to get detected by Google quickly?
 
I’ve said it before, and yes hosting plays a key role when you build out your PBN. Don’t use any shady hosting or hosting networks made for PBNs or the $1 type hosting.
 
Google has a list of all the IP addresses of hosting companies and they do pay attention to the IP address to find out where your site is hosted.
 
Here’s a PBN footprint’s checklist that I put together, you want to take a deep dive into making sure you hide your private blog network properly from Google.
It also goes without saying that you need to make sure that your backlink anchor ratios across your PBNs and all Tier 1 sites are healthy and not toxic. Read my post on anchor text optimization if you want to learn how the pros optimize their anchors to get maximum link juice for their money keywords and avoid any penalties and detections. 

Keeping Content Consistent On Your PBN 

While building out content on your PBN you need to make sure that you keep the content as consistent as you can to the original site.
 
The more consistent your content – the more it gets “accepted” by Google as a genuine site. This is obvious, because Google does not want to penalise owners of expired domains who forget to renew their domains or who sell their domain in an auction to someone else – and the site is imply revived. 
 
Because, the sites current performance is based on its content, user traffic and backlinks (amongst the thousands of other ranking factors) – keeping the content as similar as you can ensures that the sites “entity profile” does not deviate to a large extent – thereby keeping most of its ranking and performance signals intact.
 
You can make sure to keep the content almost as the original by getting from archive.org (Way Back Machine) or by using similar categories that you see there – if you must build out new content. 
This is key. Try and use the same categories if you’re building out fresh content.
If you must use the PBN to push out link juice relevancy from another niche or topic, then try and think out of the box as much as you can while creating new content or categories. Try the bridge the two niches together somehow. That is – between your niche and the niche of the PBN. Try to write an article that connects them. So, for example to bridge a PBN with content on wine to say a money site with that topic of virtual reality – you could write an article that says “Top Virtual Reality Tours of Wine Fields”.

Use A Premium Domain Name Registrar

This is a huge trust factor. Make sure that you use one of the premium registrars to register the domain you buy. And, if you have not used one – then changing your registrar does and will help!
 
The only reason why we believe this helps, is that Google wants to clamp down on the smaller registrars that are bad-neighbourhood registrars and that are specialising in getting high powered expired domains that people are then using for PBNs.
 
Google probably just wrote out a filter that penalised all links created on sites hosted by certain registrars it thought were resorting primarily in drop catching domains. Some examples are Pheenix and Dropcatch.
 
Switching over to a premium registrar increased the success rate of PBNs from 19.9% to 50%.

Auction Domains Better Than Expired?

Buying a domain via an Auction is definitely worth a lot more than picking up an expired domain. It seems that when a domain drops it loses some of its authority and power. 
 
Auction domains seem to have the ability to have the highest success rate when powering up other sites, followed by Expired Domains and then by Backordered/Dropcatch Domains. If you’re looking for a step by step process on how to find expired domains do read this guide.
 
Specifically…
75% Success with auction domains
 
55% success with expired domains 
 
50% success with backordered/dropcatch domains
 

Wait Before Your Build The Backlinks

This defies logic, but by the experiment conducted – there seemed to be some correlation if you waited for about 20 days after setting up your PBN site with all its original intended content before you linked out to your money site.
The backlink created after a small waiting period seemed to have the ability to pass down more link juice!
It  seems that it does help if you wait a few weeks after you revive the PBN site – before you drop that backlink to your money site.

Backlinks Still Counted in Expired Domains

Does an Expired Domain’s Backlink Profile Reset Once it Expires?

Absolutely not! I got asked this question just recently by a client, and while they do have a genuine concern, it is important to note that the link juice does not fall off when a domain expires and when you register it and resurrect the site.
 
The backlinks to this expired domain do not lose their value – which is why you can subsequently build out backlinks from this domain to your money site and get link juice.

SERP Ranking and Traffic To PBNs – A Factor?

The question that a lot of people building PBNs have is that –
Do PBNs need to rank or have real organic traffic coming to them – before they can pass value down to other sites?
… and, contrary to popular belief – the answer to this one is NO !
 
A PBN does not require to have any traffic or rankings – in order to be a positive link asset!
 
Let me say that again (because this is such an important result from the experiment) –
 
A PBN site does not have to rank or have any organic traffic at all before it can gain the ability to pass link juice to sites it links out to. 

Domains With A High Rate of Ownership Changes

It seems that domains that have fewer ownership changes have a higher chance of passing and the ability to pass down link juice.
 
Most domains undergo several ownership changes – but the ones with fewer transfers seems to be better for PBNs
 
The experiment saw many domains having as many as 10 ownership changes (expired / auction etc). 

Conclusion: The Winning Theories from the PBN Experiment

Here’s an interesting table that tells us the increase in probability of the key winning factors we learnt from this experiment.
 
These winning factors when combined had the ability to push more increased juice for the PBN sites.
 
 
On a closing note, I’d like to say that setting up PBNs and maintaining them is not an easy task but they do work when done right, and PBNs are definitely worth the setup and management costs associated with them.
 
There’s a ton of opportunities for all SEOs in the entire Private Blog Network ecosystem!