[Skatche]

toguilds: IC
PMs: OOC

My reasoning: With toguilds, you are communicating to your kingdom and therefore participating in an RP event of sorts. To send out non-RP messages can ruin the atmosphere for some people. If you really need everyone in your kingdom to see an OOC message, it's not a huge strain to put (()) or even just () around messages. With PMs, on the other hand, you're having a private conversation, so it doesn't really matter.