I am looking for information about loading of posts in deck construction. To be more precise, I'm not interested in how to attach members, but in how to correctly size the post itself. Looking into IBC & IRC 2006, there are specs for horizontal members (joists & rafters), but not for the posts. I have a feeling that they want to leave this to design engineers, but most of the folks I know who build these just 'wing' it. A rule of thumb would work for me, if there was supporting evidence.