In-game awards for each online match. I presume you can only earn these while battling against other people over XBL / PSN, because I haven't earned any in the single player modes. I don't remember all of the criteria, but I can tell you off the top of my head that you get the chicken medal (utmost right side, third row) by dizzying your opponent. There's also one for achieving a perfect round. From what I could tell the medals only serve as a meta-game of sorts (I don't think you unlock extra bonuses with them), but there are achievements that require you to earn a relatively large number of them.
Sidenote: you can also unlock hundreds of icons / titles for your Street Fighter IV profile. Think of Virtua Fighter 5's Quest Mode, but instead of 1st, 2nd, 3rd, ... Kyu / Dan / etc. you can handpick more "creative" ranks such Man of Meditation (a Dhalsim title) or Haste Makes Waste (which I got from the Time Attack Challenges). There are 260 icons and 430 titles, but the game doesn't reveal how to unlock them.