I personally don't like any ICO with referral bonus, this can easily be abuse, to me I believe if a project is sound enough then the project will sell out and no need to be dashing out free tokens, even project with huge bonus I always run away from it unless I participate in the presale
But marketing is one of the most important components of a successful ICO, right?
Sure it is and the referral strategy is perfect for projects that don't already have deep pockets to spend 500k on ads to promote the ICO