Still Image from the PlayStation Home Steampunk Sim, known as Nova Venezia
One of the reasons I would argue that there is a strong Steampunk presence in virtual worlds is not only for the ability to design Steampunk environs but also for convenience of interaction. The ability for a person to visit such a location easily from their own domicile plays a circumstance in the virtual experience. Second Life has been, to my knowledge, on the forefront of virtual world Steampunk locales, with such dedicated Steampunk destinations as New Babbage, Caledon, and Steeltopia, among many other locales.
Production from the Steampunker's Ball in PlayStation Home
(Mostly people standing around, but still a peek into a new Steampunk world)
As competition in the Virtual world expands, new Steampunk outposts are designed and populated, the range of experiences most certainly expands. Be it online worlds such as Blue Mars, Open Sim, or IzWorlds, or gaming extensions such as PlayStation Home, I am confident that the platform which provides the best experience (e.g. customer service, system stability, ect...) will emerge as the central location for Steampunk gathering as time progresses.
View of the Steampunk and Midway Sim in PS Home
Though the two works listed above are from PlayStation Home, an entity that I'm not familiar with (more on the X-box side myself), the production and stills show that Steampunk is beginning to expand beyond Second Life. Additionally, the official "opening" for Nova Venezia doesn't seem to be set (from what I can divine from their boards), but they did hold a "Steampunker's Ball" to present its opening. For more details on the Steampunk PlayStation world, please follow the listed links...