Slight change to matchmaking in Season 7 whereas you will sometimes be matched up against players who are much better or much worse than you.
Quote:
As a one-season experiment, we will be slightly relaxing the matchmaking settings in Season 7 to introduce more variety into the ladder. In practical terms, this means you won't always be evenly matched with your opponent. You'll regularly compete with players at slightly higher or lower skill levels, resulting in what should be a more well-rounded experience. These adjustments to the matchmaking system could also result in some players earning faster league promotions for stringing together wins against higher-ranked opponents.
http://eu.battle.net/sc2/en/blog/402...6_04_2012#blog