How do companies producing and hosting free multiplayer online games make money? Can ad revenue be sufficient for this kind of game? In recent years, real business plans that don't rely on ad revenue have come back into fashion among web startups, particularly by offering premium services. On the other hand, as competition for an individual's attention increases, inexpensive or even free is not always sufficient. I've looked at several web-based multiplayer games, and most try to put up the registration page as soon as possible to get you in the game. Once you're in and regularly playing the game, how do you translate into revenue? Only one that I saw is offering premium services. And what about games with a downloadable client? For single player web games, Flash portals have the benefit of a constant stream of people looking for quick fun, without the registration and attention span barriers. However, if a player is regularly playing and immersed in a particular web game, do they actually click on ads next to the game? In the case of a downloadable client, do they visit the game's website often enough?

Looks like you listed all the basic questions to ask, but there are no simple answers to those questions.

The details will vary based on the game. Each one is different.

You're right. Those are all vague questions, and I suppose examples of success may be more helpful than general answers. I did see a post today discussing some of these issues: http://lostgarden.com/2009/07/flash-love-letter-2009-part-1.html.