Board Thread:The Reference Desk/@comment-63.143.217.227-20130412190138/@comment-188432-20130412213230

RTD was highly resistant to the idea of any sort of serial storytelling. There are many interviews from 2005-2006 era in which he talks about how Doctor Who can't be like the then-running Battlestar Galactica because he saw intricately plotted continuity as a recipe for declining viewers and a niche audience.

The Bad Wolf thing was a last-minute addition he dropped in as an experiment to see if he could find another way to do multi story continuity in a more casual-viewer-friendly way. As he says in this old interview, it was just something he sprinkled into scripts at the last minute in such a way that he could remove it if the idea didm't work.

It has no antecedent in previous Doctor Who. Bad Wolf has no hidden meaning that references the old series. It's just a simple, childhood fairytale concept ("Who's afraid of the big, bad wolf?") which Rose uses in a time paradoxical way to alert herself to return to the Doctor's side at the Doctor's time of greatest peril. It's no more, in other words, than what it appears to be by watching series 1.

Many of the actors are still to this day confused by the concept, and there are a few DVD commentaries where a confused Barrowman implies that they talked to RTD to get an explanation and came away empty handed.

It's really just a breadcrumb trail.

One of the most instructive things you can find on the Bad Wolf "thing" is the commentary for The Parting of the Ways. At about 22'30", Julie Gardner tries to shepherd Barrowman and Piper through it all and you immediately understand it really doesn't mean much of anything. It's just a bit of fun.