30 October 2013
an unverified return means a return which was not signed by the assessee as required by the Act.
For a return filed online without DSC, you are required to sign ITRV and send it to income-tax department. If not done so, the return is considered invalid.
Normally a notice should not be issued against such return. And yes it is correct that even if such a notice is issued, the said return cannot be considered valid.