I quote from the game's site (http://forums.aeriagames.com/viewtopic.php?t=774597):
It is with a heavy heart we make the following important announcement:
Here at Aeria Games we are committed to publishing high quality games with regular content updates, bug fixes and events. Unfortunately our high standards were no longer being met with regards to Twelve Sky. It is for these and many other reasons we have no choice but to close down Twelve Sky.
We are sad to announce that due to a severe lack of commitment from the developers to fix critical issues and continue developing quality content the Twelve Sky servers are scheduled to be taken down on 4/30/2010, with the item mall closing on 4/13/2010.
Players who have contributed monetarily to the game within the last 90 days can expect a full 100% Rebate of AP within the next couple weeks (contribution must have been greater than $20 cumulatively). In addition all active Twelve Sky players will receive an email with a number of offers including special packages in Twelve Sky 2 and special invitations to the Closed Beta’s of our upcoming games.
Everyone from Team Twelve Sky would like to thank all our beloved players whom have been a part of our family that we call Twelve Sky 1. Our memories of the all the fun times and friendships we have forged will forever stay with us as we continue on in our journeys and new experiences that lie in our futures. Let us celebrate the life of Twelve Sky 1 in style so we may forever remember the good times we have had with the following permanent changes till the clock run outs.
A few of us here wanted to share their thoughts and feelings on this decision.