Good question! Still wrapping my head around it but I think it's too early to tell.

Regarding the highest zap under a note: highest bidder gets the attention. You can zap your own post with a higher amount. Both can be automated. We can very quickly get to a point where the cost/impression is not viable to use as an 'ad'.

Regarding the user getting a notification of a zap with content attached: to prevent spam we need an option so set a threshold for showing the zap or included content in your notifications. So that will solve for itself.

What do you think?