Denial of Kudos Attack on my blog

A couple months ago I set about trying to garner a few sympathy votes for my blog by complaining about the low star ratings that many of my posts were receiving. And as a demonstration of how not to carry out a controlled experiment I changed the ratings widget at the same time, from the Blogger default to Outbrain. One or other of these measures succeeded and my ratings improved no end.

Over the last few months I've been getting pretty good ratings, at a rate of about 35 a month, mostly 4 or 5 stars. It makes my heart glow rosy pink when I think that people have appreciated my work enough to rate it.

Then at the beginning of December my blog received some unwelcome attention. Logging onto Outbrain one evening, I noticed a crop of about 20 ratings, all sprung up since that morning. Odd, I thought, since that's half my usual monthly quota. And they were all angrily red - 1 star ratings - rather than the glowing golden fours and fives I'd been attracting. The next thing that stood out was that they were all from the UK (Outbrain logs IP addresses with each rating, though it only shares country of origin - it would be useful to see more details), and all posted within the space of a few minutes, faster than anybody could click through the posts. Alarmed, I checked the visitor logs on Feedburner and Google Analytics: tellingly, there were no corresponding visits logged from the UK. My conclusion? This bore all the hallmarks of a Denial of Kudos attack.

But that was just the beginning. Since then, I've racked up over 360 ratings, 1000% up on my usual tally. Most from the same place (so far as I can tell), all the same damning rating. It doesn't happen continuously; usually a block of 40 or so "spam" ratings will appear each day over a weekend, then nothing for several days.  I'm at a loss to know who or what's behind it. It's almost as if someone is monitoring the average rating, then shooting single star ratings at the blog to bring down the score if ever it rises above some mark.

Kate at Outbrain confirmed to me that it does appear to be a bot that's posting these ratings, running in an environment without cookies, which is how it evades the usual guards against multiple ratings. A few other UK blogs have been targeted, but why mine should be among them, I don't know. Outbrain manually cleared up the first hundred or so spam ratings, bringing my average ratings back up again. But more have appeared since then, which explains the current lacklustre scores. I have been promised a second spam clear out, but it has yet to happen.

Is this the handywork of some script-kiddie? Or somebody more malicious? It's definitely a very high-tech way of forestalling any pride I might experience in my work.

Anybody else suffered anything like this?