This was noted by Smedley in his Twitter account when responding to complaints regarding long queue lines and login issues. Smedley reassured in a tweet, "We are over 1000% of our pre-F2P concurrent numbers. We're very aware of the long queues and other issues. We're on it.”
This would seem to indicate that free-FTP, DC Universe Online was pulling in 33,000 concurrent users, which would contradict SOE's earlier insistence falling subscriber numbers were “absolutely not” the reason the MMO was switching to a FTP format. DC Universe Online was released in January 2011; ten months hardly seems like the normal period for a healthy MMO to transition from a $15 USD monthly subscription to a free-to-play format.
Let us know if you've sampled DC Universe Online since it went free to play on the 1st November.