It's big FOR RASMUSSEN'S TRACKING POLL, yes. But as others have said, I don't put much stock in it. Even Rasmussen himself published an analysis on Sept. 6 putting Bush's true lead at "4-5 points," whereas, on that same day, his TRACKING poll had the Bush lead at 1.1 points (and at a dead heat the following day).
By the time we get to October 2, we better be watching all these polls in terms of electoral projections only. Trends will become important in volatile states only. After all, it looks like it would take something seismic to change the projected Kerry wins in CA and NY.