Nobody plays online right now, the netcode is in bad shape. FreeSpace had a great multiplayer scene back in the day, but the netcode needs to be overhauled to modern standards. There are probably a few thousand people playing single player and co-op.
FreeSpace Open is being updated constantly! You can see new builds of the engine coming out almost every night. New stories and ships get released steadily.
The latest mod to be released will be listed on the highlights bar at the top of this website, and in the WXLauncher used to start FreeSpace Open.
There are a couple things that make FreeSpace great:
1) It has a superb flight model and gameplay setup. It's easy to pick up, but hard to master. Big huge warships actually act like big huge warships, with bristling point defenses and huge weapons to hammer each other - they're not just props. The weapons are fun, the combat's gorgeous and fast-paced, and the missions are sharp and well designed. No other space sim has ever handled the interplay between fighters and warships as well as FreeSpace 2.
2) FreeSpace 2 has some of the best story and dialog writing in all of gaming. The script is tight, atmospheric, and full of secrets and interpretations to argue over for years. The voice cast is amazing. No other space sim has managed to pull off a story as tight and thematically interesting as FreeSpace 2.
3) We've had 15 years to rebuild the engine. We made it more beautiful, more powerful, and most importantly, more flexible.
This means we can do insane, insane stuff with FreeSpace Open. We can build visual novels or let you fly capital ships. We can make FreeSpace into a horror game or a perfect Battlestar Galactica flight simulator. And we can do it all with a mission editor and a set of text files that are really easy to learn.