If you visit adCenter's home page you will notice that Microsoft now has given adCenter a logo. The logo is a oval like blue symbol, next to a small "Microsoft Advertising," with a larger "adCenter" imprint below. Here is a picture:
The logo seems relatively new. WebmasterWorld member rehabguy called the logo, "a tornado or a drain," depending on which you find "more relevant" to the brand.
Forum discussion at WebmasterWorld.