King Flevance
Deity
Sorry for maybe newbie question, but whats the difference between discussing and screenshots?
The difference is fairly small but there. If say, I roll japan when we start and I meet Chrisius to my east. Chrisius has already met DMOC of Rome to his north. Then I get a message from Chrisius that he wants to co-invade Rome, whom I have not met. He could say "They are to my north." He could even say "They are 4 tiles north and 2 tiles NE of his gold vein he knows I am aware of its location. This does help me find Rome, however, it is up to me as to what the best path through the fog is to take there. (Not all that significant) But they key thing is it is hard for us to talk about the best invasion point. I pretty much have to take his word based off a map I am not allowed to see. So really Chrisius is leading the invasion based off his strategy of the piece of the map he possesses. I pretty much have to trust his strategy instead of seeing what he sees and saying "why dont we do this". It is a subtle difference but somehow it makes enough difference for me personally (and apparently to most others) as to allow that.
This same reason effects other areas such as dot mapping terrain before you have explored it (crucial early game) and such.