I have a customer who wants to advertise on my website. Their banner size is 728x90 px. The banner looks like a text ad, I mean plain white background, the title of the banner, couple of sentences and the link their site. Since the banner looks like a text ad I was concerned that his may be against Adsense's terms. Does anybody know if my concern is reasonable?
Put a border around it, and no google markings near it, and it'll probably be okay. MSN ads look similar to Google ads too, but as long as you style them differently from your AdSense, you can (in theory) run them on the same page.
"... if you choose to place non-Google ads on the same site or page as Google ads, it should always be clear to the user that the ads are served by different advertising networks and that the non-Google ads have no association with Google."