Yesterday, Valve wreaked havoc on unsuspecting players via a 'small' bug, which was caused by the coordinator going down - as it does during patches - resulting in players gaining or losing hundreds or even thousands of MMR if their match finished during the server outage.
Even pro players like Saksa have commented on the bug (though the tweet has since been deleted), saying that he randomly gained +1000 MMR, allowing him to breach the 10k MMR mark.
The general consensus is that this bug was due to the server repeatedly trying to process matchmaking data, causing the usual losses and gains to be amplified manifold - players who won during the coordinator outage gained a motherlode of MMR, while players who lost slipped and spiraled down the slopes of MMR hell.
Odds are, this bug will be fixed immediately, so if you were looking to play 'double (or tenfold) or nothing', your efforts will likely just go to waste.
