Searching for a "song of the summer" can be a silly exercise, and the 2012 seasonal mix that is annotated below doesn't set that as a goal. Instead, it means to weave together a playlist of 2012 tunes that runs about as long as one of those full-length burnable CDs that are becoming increasingly anachronistic in a mobile-streaming-Spotifying world where iPods will be obsolete before you know it.