Flagship has launched Hellgate: London, and it's online servers. The subscription part of it is currently offline, but the regular content should be up and running. For the people that have any questions about the online game and subscriber/non-subscriber content, you can check out the Hellgate: London Online F.A.Q. There is also more information in the official Knowledgebase, and finally their e-mail.
Before Flagship Studios, there was Blizzard North. Originally known as Condor, the Redwood-based studio was acquired in 1997 by Blizzard Entertainment. At the time, Blizzard North was hard at work on the development of the game that would be the cornerstone of everything that came after: Diablo.
IGN : Remember Hellgate: London? The dark fantasy action role-playing game came out in 2007 for PC, a year before developer Flagship Studios went bankrupt. Since then, various free-to-play and online revivals have come and gone. Now, 17 years after the release of Hellgate: London, it’s back.
I remember some friends and I all bought Hellgate: London day one because it was made by some original Diablo devs. We had fun playing it, good memories.
PC Invasion: Hellgate: London is back on Steam, but it's not what you expect it to be. It's a single-player game in the vein of Asian MMOs.
The official boards are closed for outside visitors, so the used links is the best one to use. It also contains more info than just the FAQ.