I just noticed that my reputation score dropped significantly since my last time checking in. Upon further inspection I saw that on a number of older question I asked, someone downvoted my questions, one after the other. Why could this happen? Could it be a system glitch, a moderator review or perhaps even sabotage?
If you check your reputation history for today you'll find the following entry:
+10 Serial downvoting reversed
There is an automatic script that reversed such anomalous vote patterns. Those votes you see were reversed and you regained the reputation you lost from the downvotes.
It is none of those things. As far as I can tell, somebody downvoted seven of your questions because he thought that seven of your questions deserved downvotes.