> They just want to be associated with something cool, and Twitter isn’t cool

Ok. I disagree: advertising has nothing to do with coolness (the WP or NYT aren't cool, they're read by good customers). Coolness has to do with sponsorships, a different concept. Besides, while someone might notice the start or end of a business relationship with Twitter, no one will derive negative associations by a brand simply doing nothing. Unless someone else makes a fuss about it. This seems crystal clear to me.