Moving customers down the funnel has a cost.
If in the world BSM (before social media) advertising was the cost, in the world ASM this burden should be shared on more communication channels.
Organizations should choose in advance when, where and how to pay this cost and build their business model appropriately.
A generic reward, a gamification model, a monetary reward, a mix of models according to the level of the funnel?
The commercial strategy itself could change to better reflect the choosen model.
This strategic choice can be helped by a deep knowledge of what customers think about an organization, a brand, a product.
Give a look at this thought-provoking post by Angela Hausman.