Clicks still. I think, though I'm not sure, that you only get paid by impressions if the advertiser has clicked the "advertise on this site" link.
speaking of that, i came across a very strange problem. Has anyone got a solution? When I first signed up for adSense for www. aaa .com I place a few ads on that which worked out fine. From that same account I put ads on www. bbb. com and here's what happens .... when you go to click on "advertise on this site" google points users to the first URL (the wrong one) PLEASE HELP!!!
Go to your Account. Click on "My Account" - Account Settings - Onsite Advertiser Sign-up. Check the site listed there. You can only have one site listed afaik.
mooiness THANK YOU! that works out perfect! I OWE YOU! so what do people do if they have 2 super busy sites? do they sign up 2 accounts, or just deal with the wrong URL on one ...