We recommend that you visit Dunkin Donuts' Twitter account before arriving at your interview to see the types of things they post. If you already follow their account, that's great! Simply refresh yourself on recent postings, and be prepared to give a sample of 1-2 recent things you have seen on the account. If you do not follow their Twitter account, simply tell the interviewer that you do not follow it, but you reviewed it prior to your interview. Then, tell the interviewer a couple of things you saw. It will show the interviewer that you put effort into learning about the company, and that you are excited about the possibility of working there.