Yeah especially if the promotion is only for Bitcointalk users, it will attract a lot traffic because it just like a limited promotion and it will force other people to sign up in this forum in order to participate. When the promotion is available for every users, the chance to win is quite low or very low, so it's make users in this forum wouldn't participate. There are a lot casinos launch promotions only for Bitcointalk users and they're become successful.
It seems that Bitcointalk is not limited to forum members, but also of a public nature that anyone can access and visit, even though the person accessing does not have a registered account and even many casinos that have thrived before are also promoted here.
Coinplay is one of the newest examples of casinos that have grown from the previous testing process, both on forums and off. So we can see from the campaign that has been running for 13 weeks and so far Coinplay has enhanced many features and many gambling connoisseurs have joined them. In other words, the promotion they do on Bitcointalk is almost certain to have quite a wide impact and bring them to a stage of success.