It looks like in recent days Google has done some tweaks to algo and it seems that brands in certain niches have dominated (moved up) while affiliate sites moved down in ranks, in some cases couple pages. It also seems that it happened to several sites owned by same affiliates, so could be there is some changes to how Google values certain link building methods.
While I haven’t had time to fully research, it seems that it could be articles or blog comments that been lowered in value.
Either way everything indicates that one has to be using multiple link building methods to ensure stability and longevity.
This is first blog post after more than a year, so hopefully I’ll be able to get some more stuff going on here.