As far as Mt.Gox is concerned and as Genjix explained, we did not suffer any breach or any hack, all other account are safe and the thief only targeted Bitconica's account. Mark (MagicalTux) has been in contact with many Bitcoin players since this announcement and offered any help we can give, but unfortunately all funds (USD & BTC) are no longer within our reach.

Once again, someone with a US IP succeed to get Bitcoinica's account credential which did not trigger any alarms since they were fully identified. Since Bitconica's account was a verified account the owner of this account asked (This happened when Zhou was still controlling Bitconica) to have his limits lifted to the maximum possible, giving the possibility to the thief to move Bitcoinica's assets to another external account (External to MtGox).

Despite our effort on securing Mt.Gox and protecting everyone's asset I would like to remind everyone that it is also your responsibility to secure your account with a very strong password and use either a Yubikey or Google Auth (You can even use both at the same time).

Mt.Gox

-- EDIT --

We would like to stress that Mt.Gox Verified Bitconica as a Company and NOT as an Individual.