I've heard that putting images next to ads increases the CTR. I've also heard that Google is cracking down on this and not allowing it as much as they used to. (If this is a false rumor . please say so.) Anyway, I was looking through the AdSense setup tonight and noticed the referral buttons for FireFox have a the Firefox logo on them. I was just wondering whether anyone had tried putting one next to an AdSense block and whether it helped CTR much like images do.