I don't like the term circle jerks. Either the content is obviously over rewarded, or it's not. I would upvote a post I liked, regardless of who voted before it. Painting circle jerks makes it too narrow IMO and can lead to unwarranted downvotes.

Now, with obv vote swapping, and that content strangling others shot are being organically trending, can be countered with downvotes. That is simple reward disagreement, you think the post is overvalued, regardless if satan or Santa Claus voted them.