Well, long story short. Started a churn and burn tumblr 12 days ago (not so nigh competition on that niche). In day 5, it got in the first page, then day 6, I had serps like this: 5, 4, 7, 12. I had those serps for a week straight, then when I woke up today, bam ... serps: 62, 71, 63, 88. Anybody got any idea what happened? All I did what blast that tumblr with around 40-50k links with GSA, and started tier 2 to it few days ago too.