Sony Online Entertainment president John Smedley has reported huge growth for DC Universe Online since its move to free-to-play.
Smedley announced the increase in concurrent users via his Twitter feed, saying "We are over 1000% of our pre-F2P concurrent numbers."
He also acknowledged a series of technical problems - "long queues and other issues" - brought about by the surge in demand.
"We apologise for the login queues. We're working on adding more hardware and working on our servers so we don't have them."
In an exclusive column for GamesIndustry.biz, Smedley stated that DC Universe Online should have been a free-to-play game from its inception. He also predicted that BioWare's Star Wars: The Old Republic would be the last "large scale MMO" to use a subscription model.