Another possibility is that a new reader, or more than one, is reading through the archives and voting on whatever they feel voteworthy. That's fine as well.

I too have had some unexpected karma-jumps lately, and I feel the same way.

I recall this being the norm before the dark days of Euginiering.

I got this too, but I was probably the worst recipient of downvotes percentage-wise and the upvotes didn't even make up for the downvotes yet in terms of absolute karma value (let alone in ratio, which would require getting many times the upvotes).

I also noticed that my recent upvotes included a fair number of 2s and 3's and higher numbers, and there were some posts that didn't get voted up at all--in other words, they were distributed in a way I would expect if the upvotes came from multiple people. The downvotes from Eugine were not distributed that way, making it a dead giveaway that they all came from one person.

If that's a side effect of reverting the votes of systematic downvoters, fine, but if we now have a systematic upvoter, I really don't want to see this.

Given that we just got a new moderator, it might very well be that someone wants to test out the response about what happens when he goes and votes up systematically.

I personally also got similar jumps in my karma.

Now I'm listed among the 15 "Top contributors," which is absolutely not possible.