Up until now it has been Square Enix as part of Final Fantasy XI (even then they occasionally restore characters as part of 'welcome back' promotions), and Alganon's new "trial" which allows you to play for 30 days free before they wipe your character if you don't subscribe. However, as you can see from the above image, Funcom has opted to join the ranks of "will delete characters" in regards to Age of Conan.
When contacted for comment about whether or not this was true, Erling Ellingsen, Director of Communications for Funcom said, "Yes, that's correct. It's a database clean-up. We're going through all accounts that's (sic) been inactive for a long period of time, deleting characters under level 20 to free space in the database."