Very sorry to double post, but there is no edit button :P
I've just looked right down to see what people said in the last major discussion had here on improvements to make for the next version.
I noticed that Kestasjk said, when talking about a pause button, that:
"We were talking about adding a CP for games Patrick, but this will be not a trivial thing to add so whether it gets in will depend, if not now it'll be in there in a later version. "
However, after having a look at the code, I have to ask why this is. It requires one more statement in the WHERE section of the SQL, and one more field in the db to actually have it.
Admittedly, how this would be changed, such as who would have the power to pause/unpause the game, is a difficult issue, but just as turns are made, surely all players could have another option beside their moves to click, that would send a request to pause the game. If you are interested in my proposed solution, or would like assistance in the coding (since this is Open-Source) I would be happy to help...
(Sorry to those for whom i use too many technical terms)

When I say "not a trivial thing to add" I'm not so much talking about the coding, but more about the planning. I quite like how, at the moment, no player has power they can abuse, all players are equal. If I add a pause button how will it handle people who pause the game and leave, etc. If the solution is some sort of voting system that requires far more code, if the solution is moderation by an admin outside the game, that also requires more code and it requires an admin to watch over games, if the solution is allowing individual users in the game to be admin that requires a new column in the memberships table. Perhaps the solution is to give admin status to the most senior player; the one with the highest phpDiplomacy rating and thus the one that's the least likely to leave the game mid-way.
Then there's the question of what the CP will do; just pause or unpause, or will it let you kick users, unfinalize moves, etc

It's more of a problem with deciding what to do than going ahead with the decision once made, and I'd like to know exactly what the CP should be before writing anything

How about simply allowing another user to step in and take the idle one's place. Obviously certain conditions would have to be met, such as the player actually being idle. As figle will tell you (personal friend), I can only handle the logical side of coding, and although I don't know exactly how this could be scripted, I would imagine the player could be kicked from the game after three days idleness, and then the game could return to a pre-game state, allowing another player to step in. This also presents the advantage of the player returning if they were unavailable for that period of time. Once the empty slot had been filled, the game would return to its previous state. This is probably similar to the 'pause' idea mentioned above, but that had to brief a description.
Alternatively, the turn enforcement could be made shorter, which would be easier to code, and lessen how boring it would be to wait 24 hours after each turn.

Uh... This all already happens. After a country is inactive, they go into civil disorder, and another player may join the game and take over the country. A pause button wouldn't be good IMO. It could be quite annoying for some people, if its easy to pause the game, and if its hard to pause the game, it wouldn't help.

If anything, I'd suggest just a system of points, that would encourage players to play through a game, even if they are losing. Say, x number of points for winning, y number of points for surviving, and maybe losing points for losing, or dropping out.

I was thinking along those lines Chrispminis, but what effect would the points have?
If you could set a minimum number of points required to join a game you would get a split of high point games where the players are good and don't leave, and low point games where the players aren't much good and are more likely to leave. It sounds ideal but I think that the new players in new games should be mixed in with the better players if they're going to get better themselves. If there's only a mix of new players they might not get the idea behind the game faster, like what they should be communicating about, and this might make them more likely to leave without understanding what makes the game fun.

I'm not sure whether or not it would work, but it is an interesting solution.

Btw the pause button idea isn't really to do with people leaving, that's more to do with stopping players who can't access the net for a while from having a disadvantage. I think at least it should be enabled for private games where all the members probably know each other.

I like the points idea
What i meant about the pause button however, was that maybe, if three players click PAUSE then the game pauses, until less than three have it paused. That means that one player cannot cripple a good game out of spite..