I've been following the SERPs for a while with interest for several sites I KNOW are using PBN's (not a public service, a network they personally own).
Different sites with different owners, all very competitive keywords.
Either yesterday or the day before, these sites got wiped out in the SERPs. In fact there's pretty much completely new results.
Anyone else noticed this or had their sites wiped? To me, it seems Google are coming down on privately owned, secret PBN's.