Hello
I would start by saying that this is an extremely great ideas since in the past I have seen people posting about bonuses , if someone knew about those , which sites are offering and how much they are offering etc.
Therefore I think that this would not only help people but at the same time it's going to help to increase traffic on not only your site but on the main sites you mentioned too. Few things that I would like to leave as a review :

1. It's too congested therefore it would be a good idea to provide some more space in between the sites mention

2. I think that the whole site design is quite simple but there are many things happening at once and thus it can be improved for sure.

3. You should post comments and reviews of people who did use those promos and stuff therefore it would not only advertise your site but at the same time give newcomers a new found trust.