I remember a mage game played in a chat channel that I read at the GM's site. Obviously, it was edited to filter all the crap about dice rolling and such, but it was a really good reading. But I suppose that's depends on the group.
And sure, the typical AD&D campaign played by post would be very different to the tabletop experience. But I think that, realizing the differences and limitation of the play by post style, you could have a very satisfying experience, albeit a more literary one (in the sense that it gives you more time to expose your action and portray your character with more care). But I accept that I didn't played in this way, so it is all a conjecture
