Not at all. They decide what they want reviewed. Obviously we aren't the only ones doing it, some people do photo reviews, others do video reviews. What usually happens is usually something like this (which happened last week).
They contacted me and asked if I had The Mandarin, which I do. Then they asked if I had the Mechanic which I do not. So they said that they'd like us to review both figures, and they sent me a Mechanic figure. Then I usually ask questions about details of the review, for example do they want any of the Iron Man figures in a couple of the photos (since I have many of them). In that case they said no, just these two figures. When we reviewed Falcon, we also did a couple of pics of him with Winter Soldier and Cap, since all three of them are still in stock.
My Son and I sit down and talk about the figure(s) and what we like most about them, what makes them unique. We take pics of each other with them, then I take more close up, detailed pics of some of the items that we specifically talked about. Then I email them a written review and a lot of photos. They choose the pics they want to use, and usually the next day it goes up on their blog.
They know what reviewers collect and try to send them things that they would want to keep. I haven't had this happen yet but occasionally they'll send someone something that they don't want and I'm assuming when Optibotimus does figure giveaways, that is the case. You can't sell it but you can do a giveaway and drive people to your website/Youtube page etc.
Sideshow also monitors the traffic that the reviews bring in and as long as we are bringing in enough traffic, we get to keep doing it.
