As others have pointed out, this is not really an experiment for Yahoo to figure out which logo works best. It is just an attempt to shake things up, trying to

As others have pointed out, this is not really an experiment for Yahoo to figure out which logo works best. It is just an attempt to shake things up, trying to appeal to the modern internet users. You can perhaps see this more in the line of kinda-Google-doodle-but-not-really