Sony has brought its web gaming portal PlayStation Store back online after more than one month of downtime that followed what may have been the biggest data breaches in history.

In an effort to smooth things over with its customers, Sony is offering a slew of freebies, including game and movie downloads and other content users usually have to pay for.

In April, the company turned off its PlayStation Network and Qriocity services after learning about an intrusion of its system that took place between 17 April and 19 April, 2011, it said in a statement. The intruder obtained users' personal information, including names, physical and email addresses, birth dates PlayStation Network and Qriocity log-in details and more.

More than 100m user accounts were compromised, according to the Associated Press. Tim Schaaff, president of Sony Network Entertainment International (SNEI), said in a testimony in front of a US congressional committee on 2 June, that the company believed the attack was "unprecedented in it size and scope."

Sony promised to fully restore PlayStation Network in the Americas, Europe and most of Asia by the end of this week. The company said some of the services offered through Qriocity will be brought back up as well.

"The company implemented considerable security enhancements to the network infrastructure, as well as conducted testing of the payment process and commerce functions," Sony said in a statement.

During a press conference in early May, Sony's executive deputy president Kazuo Hirai said the company would accelerate migration of infrastructure that supports PlayStation Network to a new data center, whose location was not disclosed.

Systems that came under attack in April were hosted at an AT&T data center in San Diego, California.

The incident prompted US legislators to conduct a review of data security and electronic privacy issues in the nation. The task was given to the House Energy and Commerce Committee.

According to a statement by the committee, about nine million Americans become victims of identity theft every year.