Here's the comment from MtGox from around 24 hours ago:

http://www.reddit.com/r/Bitcoin/comments/1x91xq/mtgox_announ...

> Hello all. We just want to reiterate that this is not a “stop” but a temporary pause so that we can implement a proper fix to the problem. To analogize, not pausing withdrawals would be like trying to fix a car while going 120mph down the highway. The issue merely compounds on itself. This pause is clearly not ideal, but it will lead to a better outcome than doing otherwise. We’re very sorry for the inconvenience.