I also try to leave feedback - especially on EBAY as they make it pretty simple. I usually wait a period of time and it doesnt make a difference whether they have left feedback for me. I will use the "feedback within last 90 days button" and go through the list of purchases to see which I have received. I will leave appropriate feedback but seem to only get to it once a month.

Jackpot is a little more difficult (hey Dan are you out there?). I cannot remember who I left it for and with the user interface it makes it a little more difficult but I try to leave it when it is received but it usually ends up going a month down the road again...