Rosenzweig: [They're] fairly unique. Let me set up a contrast - our founders came from There.com, which is also a virtual world. The emphasis there is on the world. The geographic space is a critical aspect. When they left there and built IMVU Credits, they turned that philosophy on its head.

IMVU is avatar centric, not land centric. How that manifests itself is a tremendous amount of attention to the avatar itself. Our avatars are the most beautiful and expressive in the world.

Rosenzweig: They exist in virtual rooms, though "room" is a poor word to describe them. The concept is virtual space, which is a limited space that's can look like a room, or it can look like it has unlimited space. One can be in a coffee house, or flying on a carpet, or sitting in an airplane. Basically, whatever our developers - which we call "content creators" - can imagine, they can create.

How much of your catalog has been created by IMVU's own employees?

Rosenzweig: We have over 1.7 million items in the catalog, of which 500,000 are 2D stickers. 1.2 million are fully 3D virtual items. 2,000 were originally created by IMVU employees. Everything else is created by the [users].

Over 100,000 of the 20 million users are registered as content creators. Tens of thousands are actively creating items. Dozens have quit their dayjobs by developing items for sale in the IMVU Credits catalog, as we have a very sophisticated internal economy that supports all this.

Can you describe more about that economy?

Rosenzweig: Somebody takes the credits they get from IMVU, and it goes to the item's creator. At the point where the item is sold, IMVU takes some of these credits back. We call it a sink to pull credits out of the economy to prevent inflation.Numerically, the vast majority of people who sell those items take the credit and go back into the catalog themselves to buy more stuff.

Within IMVU Credits, there's status with being a creator. Some of them are very successful, as they've created amazing things, and lots of people buy their creations. We allow them to take those credits and trade them for cash from IMVU members, so they're in a competition with us.

We have an internal system that creates tremendous incentive, not only social, but creative and now financial, to attract the best creators. Many, many more said that it brings in a little money a month. We're proud of that.

What sort of membership levels are available?

Rosenzweig: There are others with this business model; we're not unique. The vast majority of members use IMVU Credits for free. When they initially get started, we give them some free items and credits to get them started. Most people then purchase more credits so that they can enjoy the benefits of customizing themselves better.

In just 5 minutes, you can personalize the experience, and no one would look like you. We do offer what we call VIP subscriptions - those are for people who, in addition to buying credits, get a slug of credits each month, plus free items. They also get to join VIP groups and forums. It's another way to participate.