They published the UDID numbers to call attention to suspicions that the FBI used the information to track citizens. Much of the personal data has been trimmed, however, with the hackers claiming to have left enough for “a significant amount of users” to search for their devices.
There's already a tool to check if your UDID is on the list.
I've always assumed the FBI was tracking me (and not just me, but everyone its able to) so this is anything but a surprise. The privacy crown and conspiracy theorists should have a field day with this one.