The Economist writes:
"A recent assessment of 90m such reviews by a company called ReviewPro has determined that 60% are positive, 28% are neutral, and the remaining 12% negative. ReviewPro used an algorithm to score each review (90m was obviously a few too many for the summer interns). Those scoring 80% or higher were deemed positive; those scoring 59% or less were negative; anything in between was neutral."
To which commenter Kat Matfield responds:
"I'd be far more likely to go out of my way to write a negative review than a positive one - and I work for a social commerce company. It's a little bit of hassle to write a review; not much, certainly, but it requires some motivation.
The data I've seen shows that unsolicited review systems (which I'm pretty certain is what this company looked at) get a higher percentage of negative responses than solicited review systems. When you wait for people to review off their own back, more angry/disappointed people do so than contented people."
If the problem is too many "planted" reviews, then perhaps it's time for review sites to come up with ways to verify the actual guest-generated responses. Receipt scans? Foursquare?
Send us your ideas!