There is also minor rule about combat: You CAN post out of initiative order, however, if you do your action is decided, which means that if something alters the event your action is dedicated regardless. This means you might cut down a fleeing enemy with their back turned or kill someone accidentally or attack a dead enemy (accidents certainly happen in combat).
Originally Posted by World of L_Tiene
Obviously you seem to have success with this rule, but as a player who's never run into a DM that uses this sort of rule, I have to say that it seems extremely limiting and unintuitive.
As it stands, PBP is slow and cumbersome. To make it go by quicker, many DMs have rules in place to facilitate interactions, especially combat. These rules usually encourage out-of-order posting, for the sake of speeding things up, then reordering them properly by initiative when he updates the scene.
A lot of players are aware of the stress DMs go through to keep a coherent game running that they are willing to put situational text in their combat messages (Use maneuver A, unless the target dies, then use maneuver B.), but sometimes it's just not possible to map out every possibility. And punishing them for that really isn't fair.
Take this combat situation: You have a party of 5 players, and they're ambushed by a large, albeit weak, group of goblins. 4 of the players roll well on initiative, but the last one rolls dead last. So every round goes like this:
Sorry, you just hit a corpse.
Sorry, you just hit a sleeping target, he is now awake.
Sorry, there is no longer a goblin in that square to target.
Simply due to being last in initiative, every post by that person boils down to "I attack a living enemy. No, I'm not going to specify which one, just pick one that's still alive when my turn comes up." Spellcasters are especially crippled, because of the potential of wasting their finite allotment of spells on hitting nothing but air.
It's a simple issue to change attacks to an appropriate target if the original target isn't viable once the player's initiative comes up. I just feel that your rule, as it stands, stifles in-combat creativity and roleplaying.