According to the BBC, Graham Cluley, senior consultant at security firm Sophos, said that the reason Anonymous fell victim is probably human weakness.
Chances are that they followed poor password practices, like using the same password in multiple places or choosing a password that was easy to crack, the expert said.
He said that everyone should learn better password security from incidents like this, adding that if it can happen to an account run by Anonymous supporters, it could also happen to others.