The game ended and my rating didn't change at all. Why?
There are a couple of reasons this might be the case.
First, keep in mind that not all games are rated, so your opponent may have opted for an unrated game in this instance. Check the "Details" tab (next to the game board) to see if it was a rated or unrated game.
(During a rated game, you can also use this tab to see a preview of the ratings changes. Just click where it says "show rating adjustment.")
A less common case involves users who have timed out in more than five consecutive games. Once this happens, the system assumes that they have simply abandoned the site for some reason. After five games have ended due to inactivity, we stop making rating adjustments on further time-outs in that user's games. This is to prevent arbitrary ratings inflation.
Keywords: rated, unrated, rating, change