The IGDA commissioned an Online Games Committee to address the needs of game developers concerning online games. The purpose of the Online Games White Paper is to provide online games market statistics, business model descriptions, technology summaries and publisher listings. Additionally, this White Paper provides online games case studies and reference resources.

You need to be an IGDA member to get the white paper, so I haven't read it yet. But decent market research is definitely one of the few things that might make an IGDA membership interesting to me.

In-Stat/MDR has released an online gaming report. Some of the conclusions from their press release:

The high-tech market research finds that while online gaming won't take over the world, even a moderate number of gamers (such as 10% of the game consoles), playing for relatively short periods of time (5 hours a week), would consume more than 5% of all of the American Backbone Traffic by the end of 2003.

...

The biggest risk to any company that is even marginally affected by online gaming is to dismiss it out of hand or put plans on the backburner until they think it matures. There are a lot of companies that are working very hard to grow this industry quickly so, odds are, they will help to move things along, faster than some expect.

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The combined data throughput for both paid and free online console gamers will top 285 Petabits a month by 2007. At the same time, the paid console subscriptions will bring in just under $650 Million. However, as it currently stands, none of that money will end up with the broadband providers that are handling these hundreds of Petabits of additional data.

You can read the abstract for free. The whole report costs $2,495.