I agree in 100% !!!
+ "0 fee" for sharedroping.
Maybe this could be some new type of transaction.
I think STEEM has a TX-limited allowance for free transactions. Maybe a peek at what they're doing for guidance.
When I read the original post, I balked at the "upper-limit" suggested. NOBODY will pay $100 for a blockchain transaction no matter how much the transferred value. The fee should be commiserate with the strain on blockchain (transaction network and storage cost, etc). That said, maybe something like $0.10 - $0.20 might work, but I wouldn't push it too far else you drive away users.
It is quite possible I don't understand the suggestion in relation to bots... Do remember that bots are already paying 0.05% to 2.00% to trade in some UIAs. Perhaps adding a fee to committee-controlled SmartCoins could be added for some purpose (maybe as mentioned in your other thread?)
Now, to combine referrals with my favorite love: Bitshares bots!
If *somebody* could make an easy-to-use lightweight cross-platform bot CLIENT, they could integrate themselves as default referrer (or even registrar) for all these new bot accounts! (Now THERE'S some potential for getting meaningful referral fees!) Ideally this client would have built in wizard and analysis tools to help determined users find most profitable trading strategies.
Anyway, I do not wish to detract from useful brainstorming. Thank you for your ideas. There's some in here worth discussing and hashing out.