When residents buy a whole island, they get dedicated use of an entire Intel- or AMD-based server, with pricing based on the processor, memory, and storage of that server. Landowners aren't locked down to a particular server, though -- Linden Lab moves sims around for system maintenance or if there's a server crash. But landowners' fees guarantee them to access to particular classes of server, with particular processors, memory, and storage allocation.

For now, Linden Lab is the only company that runs sims. It derives the majority of its revenue from land sales. However, that will change, as the company is committed to allowing others to run their own sims on their own servers.

While many Second Life residents are convinced that Linden Lab will release the server source code as open source, in fact that hasn't been decided, says Miller. Linden Lab might simply decide to license the code to other companies, the way vendors now license any application. Linden Lab might publish all the APIs, and allow other companies to build clones of the Second Life sim software. Linden Lab might simply allow other companies to provide the hardware, which Linden Lab would run at its own co-location facility, running Linden Lab's software. And there are other options as well, which Miller declined to elaborate on.

Linden Lab opened the source code to its client software, which runs on Windows, Mac OS X, and Linux, in January, and the company is using that project as an opportunity to learn about governance of open source projects, says Ondrejka.

The servers support 34 terabytes of user-created content, and the traffic load for accessing that content is very different than a conventional Web site. "If you think of a Web site like Digg, there are relatively few creators of information, and lots and lots of consumers of information. In Second Life, the equation is different, in that two-thirds of the users are actively creating content over time."

To help manage growth, Linden Lab is looking for IT staff who have done it before. "We're looking for an operations-specific person who was involved in scaling a server farm from where we are today, which is 2,000 boxes, to 10,000 boxes. There are very few people in the industry who have done that," Miller said.

Linden Lab went live with its Dallas co-location facility in December. "We're consuming a lot of floor space. It makes sense to have it geographically distributed. It creates redundancy and backup. If we lose bandwidth at one facility, we can shift load and resources to another location," Miller says.

Since then, residents have expressed concerns that the split locations have contributed to performance slowdowns -- which the residents call "lagginess."