When I was in Vietnam last year I booked a few cheap hotels in the 10-20 U$ a night range (nice ones by the way!) on Agoda.com.
Often the reviews went like "best breakfast in Asia" or "I will come back to Vietnam just to stay in this Hotel" but when I went there, they where nice but not THAT nice.
Once I went here
http://www.agoda.com/asia/vietnam/hoi_an/sunflower_hotel.htm... as the reviews where incredibly good: but as I found out the internet was very slow, breakfast was a deception, the reception a bit rude and they even gave me a smaller room.
So I wrote a review adding to be careful about fake reviews.
Sure enough Agoda did not publish it and they did not even respond to my email asking why.
I did not expect a Facebook debit card but at least a "thank you" :)
After all I helped them spotting cheaters!
I was completely ignored.
The result is a side flooded by fake reviews costing a couple of bucks each to the Hotel manager.
That's cheaper than Adwords :)