I don't think it was a widely publicised as say SCD and other programmes have been. Other than that I don't see that the celebrities are any less 'celebrity' than other years.
Main show 2009
Week 1 - 8.4m
Week 2 - 9.2m
Week 3 - 8.3m
The Skate Off 2009
Week 1 - 6.3m
Week 2 - 6.7m
Week 3 - 6.5m
I think Week 4 will bounce back around the 9m mark with the Todd Carty affect. But the main shows are only slightly down on last year (though the 2008 launch claimed 9.11m).
The Skate Off has obviously been hit hard by it's later slot, which is a joke TBH. But combine that with the fact that Sunday nights has been weakened overall by ITV1 (with BBC1 more resurgent than last year after ITV1 mucked about with their big hitters) and I think the main shows are doing well.