Comment I think there has been a change recently (Score 1) 201
I am also in Vine, and I don't think I am more generous to the free products that I get. In fact, it is sometimes the opposite, as Vine almost by definition provides things you don't really want, and I'm less likely to give a strong review to something I don't really want.
Membership in Vine makes me sensitive to the number of reviews each item on Amazon has, and I have recently noticed that the average number has increased dramatically. It used to be than an obscure or expensive item had 2-3 reviews. Now, virtually every item I look at has hundreds of reviews. Yesterday I called up a newly released $2500 camera lens to find that it already had almost 100 reviews. It feels odd to me, and I suspect that there may be astroturfing taking place on a massive scale, but I have no way to prove it.