Finally we heard back from the marketing person in charge of this decision. And the answer is: YES!
Adrien, under separate mail I've sent you a GIF file of the Chirp Intel Threading Building Blocks 2.1 logo. As long as you don't modify the image (in particular, removing the product name), you're free to display it on your TBB-related website(s). Once again, sorry that it took so long.