Yeah could be some kind of a delay in your stats (happens sometimes afaik @ CB), could be luck, could be someone who referred the product to some of his/her friends
Could be a delay, could be sudden interest (tell a friend, etc etc), a number of things. Sometimes it's just CB testing their product checkout page, which gets annoying. but 4 sales per 23 clicks seems pretty nice I have some days where my CTR and conversion to merchant pages seem very low, and then my sales are abnormally high. All part of the ebb and flow, I guess... -T