<p>I know my recommender got one, and many others have posted about this in the past. Not uncommon, depending on your regional admissions rep. Doesn’t mean anything about your admissions chances.</p>
<p>No, it is not rare. Period. I don’t know what you mean about the alum, but what matters first is your actual app and recs from those who know your academic performance based on classroom experience with you.</p>
<p>It is a curtesy and it is polite. It’s like sending a thank you note to your host after a sleep over. It does not mean you found the bed comfortable. But your letter writer contributed to Brown’s admissions process so they sent a thank you. It is good PR for the school.</p>
<p>My understanding is that this is more a reflection of what admissions thought of the recommendation and not what it thinks of the student. Brown is saying to your teacher, “Thanks for writing such an awesome letter, it gave us so much insight into this student and that helps us so much in the admissions process. We wish everyone wrote as well as you. Keep up the good work.” Most recommendation letters are very boilerplate, and when one comes in that is thoughtful and insightful, Brown wants to thank the person.</p>
<p>You the student still has a 92% chance of getting rejected. For all you know, the letter could have subtlety explained why you’re not right for Brown.</p>