ANN threads are effective for sure. But i am not sure about bounty campaigns. There are so many bounty hunters they open useless social media accounts to get more free tokens. A more professional advertising strategies are a must for icos.
The best way to pomote Icos is using social media. People nowadays are into social media. You can advertise od promote such tokens in a creative manner. And the message can easily spread to billions of people because of internet. However, there are disadvantage like they cannot easily determine whether it is reliable and trustworthy or not. But you can caught the interest of a lot of people. You only need to be factual and purposive.