When comparing the results from 3 people on this board with multiple website's i can only conclude for now that the latest update has a linknetwork detection in it which is easy activated when the linked sites are using the same IP range.
For now tests are made by removing those links and another test is to move a site who is affected to a totally other server...and maintain the links.
Still there are questions.
Is there anyone of this board who has only one site with a problem after this update ?
For the ones that do have multiple sites....and don't have problems.
(1) How you link your own sites together....
(2) How many links has each site in your network from other sites outside !!
(3) do your own sites have the same provider...and what about the IP used.
What i noticed also with the network is that the site with the most authority in this network is replacing others in the serp who should be there, but are out.
I am convinced that certain link structures who where not seen before as abusive are now being punisched by kicking out the less authorative site in the network.
The same IP or BLOK of ip is for sure involved in this matter because else this knowledge could easy be used to kick out any competitor by linking on it with some very authorative sites of your own.
My advice to others is that if you have sites that should be linked together in a network, then use different servers for it...and never in the same IP blok, this
to prevent an unnatural link scheme.
(because how big are the chances that 2 sites linked on one server are not from the same owner )
You can run them on the same server and even link them together....but not
only with those links which you provide yourself.
regards,
OPtimizer