UPDATE: 2014/3/6 These issues have been resolved.
We acknowledge and are aware of the increased number of “unconfirmed transactions” in some cases. We are working on ways to address or at least reduce this issue. Rest assured the transactions will either eventually go through or the funds will be returned to the sender. No funds are lost. There is no need to resend the transactions unless the funds are fully returned to the sender. We understand and apologize for the inconvenience, and we are working to resolve it as soon as possible.
If you are experiencing this issue, please contact us at https://blog.blockchain.com/support/