I made ribs for the first time, and they turned out great. But I noticed there was a pinkish ring in the meat. Did I do something wrong?

On the contrary: You should pop open a bottle of Champagne (or microbrew) and celebrate. The pinkish ring is the smoke ring—a natural chemical reaction that takes place when meats are cooked low and slow in the presence of abundant wood smoke. Pit masters call it a “red badge of honor” (with apologies to Stephen Crane) and it lets you know you’ve smoked the ribs (or brisket or pork shoulder) to perfection.