Does Flarum use websocket?

I'm wondering if flarum makes use of websockets? Or is it just plain ajax? Can we really use the threads as real time chats?

When using Chrome you can take a look at the 'Developer tools' -> 'Network' tab. It shows a websocket connection initiated from pusherapp.com

Yes, the Pusher extension uses Websockets.

It still needs to be improved a bit to give you anything like a chat feeling...