I was going through my match history in League of Legends after losing a few in a row to see how long it's been since I've won a game, and I saw this:
The game was a few days ago and I unfortunately do not have a very good memory. What on earth does "Loss Forgiven" mean? Usually that line either says "Victory" or "Defeat".
If there are server issues during your game that Riot would consider serious enough to affect your gameplay, then any loss will be forgiven due to circumstances outside of your control (source). This means that your elo and win/loss stats are unaffected by that loss. However, if you win your elo will only increase by half of what it normally would. IP and XP are gained as usual.
I don't believe they forgive losses for teammates leaving the game though (JesterCapp discusses that here).
