DarkNecridI understand your reply to me Jon ....
Sure, if you haven't watched the video linked at the bottom of page 3 it should answer some questions, Robin Walker puts it better than I ever could. It also addresses content similar to the battlenet forum post you link in some respects, in that they probably want to tell people more about matchmaking and mmr in order to inform players and therefore make the quality of community discussion about it more likely to be useful when developing the game. Valve have done that for Dota and may do it for TF2, although I don't think they've said much about CS. It's important to recognise that stuff like that isn't done just to be nice or useful, they expect to get something back.
If you're not talking about the kind of hype type marketing that other companies put out as "communication" then questions about involving marketing decisions at an early stage don't arise along with the organisational problems it might cause. Outsourcing that kind of thing is hard because they take a long time to plan and they want concrete information while the devs want the flexibility to change things and also to ship early. There's inevitable conflict there and it's very much a dev driven company so I think that's limited to events like TI.
The frequency of blog posts is also addressed in the video towards the end - the less frequent the better because of rarity value and I think they would treat Valve visits and b4nny teases in a similar way. I guess what they've allowed to leak through b4nny is what they're comfortable with people knowing, although for some it's obviously not enough.