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.
I'm agree with you, many bounty hunters who only spam social media campaigns. They only do continuous repost. This seems very unprofessional.
It's better to make a post than just repost that seems trashy.