It may become a FUD for cryptocurrency in the short term but eventually when the developers of the coins will be able to deliver what they promise and follow their whitepaper then they may allow again the advertisement of some cryptocurrencies. I can see now that they still allow it but it is not surprising they would ban it because of what facebook did. Sooner or later, other social media platforms may follow them and the only way for the ICO to advertise is through its bounty participants.