"Was this review useful" button earns Amazon $2.7bn
uie.com
uie.com
The first day part is key here. In my experience writing many and reading more reviews on Amazon, being first to post is key in having a review marked helpful.
Also, though they've apparently done some things to prevent the most straightforward gaming of the system, there are huge, obvious holes for abuse.
Consider SimCity[0]. The review section is worthless. The spotlight reviews are all 1-star rants. The most helpful 5-star reviews are sarcastic rants. The only remotely positive reviews, genuinely helpful reviews are buried.
The Amazon review section is a battleground for all sorts of Internet wars of preference.
I'm a fan of the recent "X reviewers made a similar statement". I've been hoping Google would introduce something similar for the Play store.