Looking forward to these posts. I've remember being completely fascinated by Diablo 2's virtual economy, and saddened that I could find so little articles about it.
I went to GDC this year and saw a talk by a PHD Economist who does work on video game economies and releases reports about them. It was one of the coolest talks I attended, and I spoke with him afterwards. In his talk he mentioned Habbo Hotel a lot and spoke about a few other economies and how they came to settle on some sort of currency. I just had to bring up how I first noticed a form of virtual currency in Diablo 2 as he didn't seem to mention it. I do recall that SOJ's were like the defacto unit of pricing other items. Apparently he had actually never heard about that, which surprised me greatly (perhaps because Diablo 2 was so huge, and because it was one of the only examples I personally had). Here's hoping he looks into it and writes a report about it!