ohh that coming soon , starcraft 2 season 3 will be locked in some days/week and ladder reset once again xD

They expect to make seasons very short it seems , +/- 2 monthes.

more infos on the official blog

http://eu.battle.net/sc2/en/blog/3075979/Season_3_Lock_Incoming-06_10_2011#blog

Blizzard wrote:

after leagues are locked, players will still be able to play out their remaining bonus pool and compete for standing within their divisions until the end of the season two weeks later. The match-making skill ratings which determine league promotion and demotion will also continue to update during the lock, so games played during the lock still count toward league placement in Season 4

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