First off, welcome to the forums, Eltanin! I'm sure you'll love it here.
Well, the online community is thriving still, although most servers use mods. Some of the most popular ones I have played are:
Evolutions- My favorite large mod out there. Evo adds tons of new ships, weapons, and features, yet still remains true to the Freelancer story. It can be played in SP, OpenSP, and many servers run it for MP. The latest version is 1.30. There is also Evolutions: Nomad Revenge, which is similar to Evolutions, yet has some new elements. The latest Nomad Revenge version is 2.29.
Freeworlds- If you like Star Wars, this is a major Star Wars Total Conversion. It has all the best Star Wars ships, and is played on a variety of servers. Other SW mods include Tides of War and TIE Universe, which are also top-notch, although not quite as big as Freeworlds. Freeworlds is on version 1.65, but version 1.66 should be coming out soon.
The Next Generation (TNG)- I haven't played this mod much, but it is highly popular. It is a total conversion mod that totally redoes Freelancer with all-new factions and ships and weapons. The latest version is 2.76, I think.
Warriors of the Sky (WOS)- This is an interesting mod made by the genius Argh that converts Freelancer into an old-skool prop plane and ship fragfest, with totally redone systems to make it so you're flying over land and water with cities instead of stations and everything redone completally. It's still in beta, beta 2 or 3 I think.
Asgard- This is a roleplaying mod that adds and changes a few interesting things to Freelancer. It adds new weapons, and replaces every Freelancer ship with a custom one. It has a server specifically for the mod, "Asgard RPG Server", and they have a pretty good community with a large variety of clans and a lot of dedicated members. The lastest version is 3.11
Anyways, those are the 5 biggest mods I've played. I'd recommend trying out the mods on OpenSP Lite first to try them out and see which fits your tastes before going online with one.
Enjoy the game and mods!