Interactive or participatory - Jill's question from nov. 1st, what I think of this distinction.
I think interactive demands some kind of response: I say something to you, you say something to me in response to that, and you and I discuss or do something together based on our agreement, our actions influencing the other and their actions influencing us.

Participation does not have to include a response though. I can participate in building a wall through lifting one stone or fifty, and I can have the satisfaction to see the stone I put into the wall afterwards, but my participation might not matter to the fact that the wall is being built. I did not change the wall, since the stones I put into it would end up there anyway, I did not influence the structure, and I had no response from the wall or the builders of the wall to my contribution, but I still participated.

With interaction, the reward is the influence you have on the process, with participation the reward needs to be something more than the process: being able to take shelter behind the wall, have a meal and the company of people you like, or getting your name in the paper as one of the participants and gaining social status.

What does this mean for computer games? I think most (if not all) are participatory, while the ideal is interactive. Problem is: so far only living beings, humans most suitably equipped of those, have the ability to interact. Interaction demands a level of self-consciousness computers still don't have. Participation is a better word, because it doesn't require the software to acknowledge us. As to participation already being used on something other than software (participatory art, theatre...), I can only wonder if the programmers think they invented interaction.