Well, I had booked the ad to run from 6am Thursday to 6am Friday.
Didn't realise it had to be approved by an office run on Pacific time, so it only started to run around noon orso (not sure of exact time)
I checked a couple of minutes ago, and had one click recorded from almost 9,000 'showings', at a cost to then of $2.25.
Will check to see if they went on to the smashwords site.
Maybe a pay-per-click option would be better? At 47cents or so per click I want to have returns- come to that, that is still better than present option.