Ok, so in this thread I'm going to shed some light on potential reasons that private blog networks are getting shutdown. 1. Matching Link Patterns: This is when multiple domains have the exact same back links (root domain match). Therefore, even if you're on a subpage the network will still take a hit. 2. Giving out reports: Although we all love reports this has got to be the easiest and fastest way for Google to mass de-index sites. All it takes is one pissed off competitor or Google employee to find out this list. 3. Mass Link Blasting: If everyone is pushing 100K backlinks across a 1K domain network * 100 customers each site will most likely take a penalty for suspicious high volume link building. 4. Keyword tracking: When everyone of your backlinks come from a High PR website it gets a little suspicious. Therefore, a manual review of your site would reveal a dozen different networks and they all would take a hit. 5. C-Class IPS Too many of you think C-Class ips make you invincible. This is not true. All Google needs to do is see that they are all from the same web host and BAM! They caught your network. You truly should not have more than 5 sites per web hosting company. YES this means building a quality network is about to get really expensive, but it's the only way you will survive in the end. 6. So, you think you're clever with no reports... Reports or not all Google has to do to shutdown a service like BMR or any other link network is use a fresh domain and track all the backlinks for that domain. GAME OVER! 7. Too many topics Having an authority site is one thing, but when your blog covers 1,000 topics and has posts flying out every 30 minutes it's a little obvious something is going on. 8. Spun content Spinning content 1-100 times is usually fine, but on some services they are using the same damn article for 1,000 blog posts. That's a large enough footprint to pickup on. DUH!?!? 9. New sites It's a proven fact blog networks work. In fact they are THE NUMBER ONE working strategy to date that I've seen. The results are impressive....... or are they? The problem is when a new site ranks in one week (which I've done regularly using PBNs) it raises RED FLAGS and fast. So expect a manual review. READY TO CRY??? Google takes a look at your backlinks, figures out that you're using a PBN slaps you and the entire network. TRUST ME. I've seen sites keywords repeatedly get de-indexed completely for using PBNs. 10. Limited link profile For sites that don't have a diverse link portfolio it's a piece of cake for Google to figure out where you're links are coming from, detect the network, and shut you and the network down. PS: For all you PBN owners. I hope this sheds some light on why your network tanked overnight. Stay tuned for my post "How to avoid getting your PBN from being shutdown" coming soon to a BHW thread near you.