Yeah, he actually means the DC Animated Universe which has a whole wiki page dedicated to it. It includes quite a few TV series, theatrical and direct-to-video films etc. which all spawned from the world of Batman the Animated Series and share the same continuity unlike most other DC animated shows from before and since then which tend to take place in separate, individual continuities. Fans tend to refer to this particular continuity as the Timmverse due to the heavy influence of Bruce Timm who was the shadowy hand behind these productions in one capacity or another, and the universe did take cues from his distinctive artistic style.

It's a shame that many cartoons are being mistreated while networks focus on just a few franchises. The Legend of Korra suffered from network politics as well, and I won't be surprised if several intriguing future shows will fall into the same trap eventually when the suits make yet more incomprehensible decisions. It should be interesting to see if in the future we'll see more animated shows based on films like Tron: Uprising which was based on the Tron universe although I'm not holding my breath.