Are we going to see the crack in every single episode this season? We already have in the first three episodes...the thing with Bad Wolf was that it was more of a subtle thing you saw it in places and episodes every once in a while. To be honest I noticed it myself a couple of times and then made the connection when the Doctor did but he dismissed it at first and then of course Rose made the Bad Wolf connection and figured out what it meant. The space crack thing it seems we're getting bashed over the head with and I'm convinced that it is the TARDIS that is bringing the Doctor and Amy to places where the crack has affected time. It will be curious to see where the crack is in the two parter.