The greatest power of blog marketing comes from the viral effect of some blog posts. News travels very fast via blogs. Readers pick up interesting stories and blog about them on other, third-party blogs. Their readers in turn spread the word to others. All this is done at very little cost to the advertiser, and often has a snowball effect that can be started off with just a few strategically placed blog entries and comments on others’ blogs.
While blog marketing presents a fantastic opportunity for marketing agencies and businesses, it can be a dangerous medium, as originators often have very little control over the message that gets spread. If users perceive the blog marketing effort to be objectionable, they can easily turn the tables and create a PR nightmare for the advertisers.