Currently a lot of people write BLOG's because it has become quite easy. Those writers also realize that the visitors aren't coming that easy anymore, because the social media bring much more diversity. So what happens? The BLOG-writers post links on their Social Media Websites like facebook and Tumbler, and also send out Tweets to their followers to draw attention.
That worked quite well for the last years, but now people seem to not follow those links anymore. The BLOG's form an undiscoverd archive of information that most Internet-users are avoiding. A new marketing tool will be brought out soon to solve this. Not sure what it will be.