12 hacks in 46 days. That's a rate of 1 hack every 3.83 days. And that means we can expect to see it get hacked again by Thursday this week. Everyone keep your eyes peeled!
Do you really think every time Sony is penetrated, it's announced and everything is dumped like Lulzsec and other loud mouths do? The much more likely thing is that these vulnerabilities were known for quite awhile before.
http://attrition.org/security/rants/sony_aka_sownage.html