If you are building a PBN (Private Blog Network) it is incredibly important to hide your footprints. I recently found this Video on Youtube where pretty much everything regarding this topic is explained.
There was one point however that I found really interesting. Google Tracks you using Google Fonts.
Avoid Google Font Tracking
So if you use Wordpress for your PBN and you login to maybe two PBN-Sites with the same IP Google has you.
How does that work
Whenever you request a Google Font your Browser sends a request to Google to download the font. However it also sends the Referrer-Header with the page on which the font is embedded.
So if you login to your
examplepbn-1.com in the Wordpress Admin-Panel then Google gets your Home-IP and the name of the site. If you then login to your other PBN site like
examplepbn-2.com then Google has the same Home-IP and a different site. So now Google knows you have a PBN and the seemingly unrelated pages are ultimately administrated by the same person - YOU.
I found that fact really interesting and thought about what you could against this.
Remove Google Fonts from Wordpress
There are plugins out there which remove Google Fonts from Wordpress Admin-Panel as well as Themes. The only problem with that is, it could be used as an indicator for a PBN. Who else removes Google Fonts from Wordpress?
Also you have to do this via FTP preferable before you login or request the site for the first time. So you stay hidden right from the beginning.
Use Proxy or VPN
You could just use a proxy or VPN so your IP is not the same for each login. But it is likely that Google tracks open proxies and VPNs and maybe also uses this as a kind of flag for PBN.
If you have to many flags you risk a penalty or manual review.
Prevent Browser from downloading web fonts
This is the way I use now. I configured my browser to not download any web font (not just the Google Fonts). And I use that specially configured Browser (Firefox in my case) only for the PBN work.
The only drawback is that many symbol fonts are not loaded which makes working with some sites (including the WP Admin-Panel) a little bit harder.