A couple days ago, I noticed that three my questions on Meta Stack Overflow were downvoted around the same time.
Yesterday, this question on webapps.stackexchange.com got two downvotes at almost exactly the same time (even though it was a relatively obscure question.)
Additionally, three of my questions on Stack Overflow were downvoted today (apparently at random) within the same hour:
So I'm still not sure why several of my questions (especially older, more-obscure ones) are sometimes downvoted at the same time. Are these random "downvoting sprees" likely to be intentional, or is it more likely to be coincidence?