Opel Blogs : Credibility discussions

In Germany the car manufacturer Opel has started a blog project to promote the new Opel Astra. Four bloggers are equipped with the new car for four weeks in order to test and review.
All the blog posts are sydicated on the Astra blog astra.blogg.de/.
Moreover, there is a sweepstake where users have to send pictures of the Opel bloggers.
The fact that the bloggers are sponsored with the car and the allowances are paid had kicked off discussions in the blogosphere about credidibility and the sell-out of the bloggs.