While you would have to have your head in a hole to not know what the DS is, there probably are people out there that don't and now they are curious.
Its interesting you say that, from my experience most people, including a lot of gamers, have no idea what the Nintendo DS is. Hell, my buddy who came with me to E3 last year doesn't recall what it is and he probably saw it at some point. This marketing campaign, I believe, is really for those who are completely in the dark rather than those who are aware of its existence, not to mention its capabilities.