Updated Wed, Oct 19, 2011 by Martuk
In short, no credit card details were compromised but an issue with forums for The Lord of the Rings Online allowed unauthorized access to the forum database. Some players may have received an additional email that indicated a changed password along with recovery instructions. Turbine made the password change to a few select accounts as a precaution.
The FAQ also included a few tips on password security and how you can choose an effective password to better protect your account. For now, Turbine has made changes to their forums to enhance security and players should do the same for their account passwords.
Thanks to Gunky for the catch.
Source: The Lord of the Rings Online Security FAQ
Original Story: Turbine Addresses Recent Forum Outage and Security Concerns