According to the Nikkei Search Data Signal, 76.2% of Japanese Internet users are aware of blogs and the recent upsurge in their popularity. The survey also reported that 32.4% of men and 47.1% of women buy products that were introduced in a blog article. As for what types of products are being bought; 35.1% are books, 26.9% food and 23.1% is electronics. Based on my understanding, it seems like the data is related to products that are written up in blogs instead of regular blog ads.
The original Japanese article can be found at the following link:
Posted by tonytorres 
MediaScope - Keeping watch on the Japanese web and mobile media industry 