In my opinion, this study does not provide the answer to that question. It merely indicates that people do not research products on blogs. I have no doubt that this is true. It seems obvious that if shoppers want to research, they are going to go to highly authoritative sites. However, that does not mean that blogs do not offer marketing opportunities, and I know for a fact that blogs do generate sales.
Here are three benefits to blog postings:
1) Overall buzz about your company and products.
2) Consumer referrals. If credible and visible people talk about your products, it will help your sales. In fact, we track sales every day back to blog posts and forum posts.
3) Inbound links. Frankly, I think this is becoming less and less of a benefit as Google and other search engines continue to devalue these links.
So, should blogs be part of your marketing strategy? I would say yes. However, like I would say for most other online marketing efforts, focus on quality rather than the quantity. Hundreds of posts on spammy blogs could hurt you more than help you.