camapigns signature is very useful. Since Bitcointalk has a lot of views, this campaign causes many people to know the project. But this campaign does not cause ICO to be a success. As I mentioned they only help ICO to be known by more people partly from promotion.
bitcointalk doesnt have a lot of views rather , this forum has a lot of members and that is equal to more traffic resulting for it to appear in the first pages of google search results. most members here do also invest their earned coins to the ico that theyve joined or like therfor bitcointalk.org is an overall hit for those who want to advertise their ico in the form of signature campaigns. Not just ico but members can also benifit from campaigns as they can earn A coin and token that they can exchange for a real cash.