I ask this as I wrote a knol on the current 'gas from water' craze, pretty much debunking it (but with a few affiliate links in - if anyone wants to check out one of these systems after reading what I've written, I'm happy to accept commision!), which fairly quickly received a one star rating. I looked at a few other knols on the subject, which were essentially sales pages, and they all had higher ratings than mine. Just to see what happened, I got someone I know to give a high rating using their account, which took my article to 3 stars, a couple of days later it was back down again after being given another 1 star
Of course it may just be that my page is cr@p and I'm being far too suspicious, but I think the system is open to abuse. What do others think?