Hello mates... About 1 month ago, I changed my Adsense Account (one Personal to a "business" one.) But, in the SAME day that I changed my account, my site dropped hard in Google SERPs... It was in the SAME day, and it's really weird... Can change adsense account affect the SERPs?
I dont really think it was because you changed accounts. It would be really stupid if changing adsense accounts effected serps and I am sure it dosent, maybe just a conincidence where something else went wrong.
It MAY effect your SERPS as there is a theory or " myth " that your adsense account type relates your content type to either being personal or business related. Research is required on this topic i think.
It must have been a coincidence, there is no way that Adsense can affect SERPs. Google SERPs move around all the time.
Changing adsense accounts will probably not affect your site's SERPs, but if someone from Google did a manual review of your site and saw that it was "spammy", they could deindex your site entirely. Since that didn't happen (you say your site only "dropped"), then it's probably just a coincidence.