The Rock, Paper, Shotgun interview recently posted with noted Massive designer Raph Koster starts off "Raph Koster knows a thing or two about MMOs". That's a bit of an understatement. Looking at Raph's CV is like stepping back through some of the most important moments in the online gaming genre. Most of them, as has been the norm in the USA, are subscription titles.
Raph thinks that's quickly going to be an artifact of the past, as already there are more free-to-play games than flat-fee-per-month titles. He believes that big budget games are going to start to get the hint and offer tiered services, free-to-play special clients, and other ways to get an 'in' on those particular worlds.
Ultimately I think that's one of the most important points he makes in this discussion. MMO developers (in the West at least) have always seemed to be resistant to the idea of 'just get everybody you can in there'. That seems counter-intuitive to me, because more than anything else butts in the seats are what makes a Massive environment seem truly alive.
The rest of the interview is equally thought-provoking with discussion of the concept behind Metaplace, the misuse of the web by game developers, and the conceptual skeleton used by designers to make these games in the first place.
