There is someone around 60 million blogs on the web (Technorati, 2007). The majority of the sites only receive a few visitors. The top 100 blogs receive 15-20% of the visitors while the rest receive only a few.
Most of the bloggers aren't professional writers and journalists. That means they borrow the information from somewhere else and aren't necessarily liable for that information. Since most are not professional writers there is the possibility that the information they are offering is questionable.
Many bloggers are not the author listed on the site. “Ghost Blogging” is also fast becoming a reality. Let us say you are a company, a politician or some important person. You certainly don't have time to write on your blog all day. Ghost Bloggers are people who write your blog for you but don't put their name on it.
Bloggers can get more hits by having links. The more sites that link to a blog and from a blog the higher it gets on the page ranks. The higher the page ranks the more visitors it gets. Thus, writing articles, posting reciprocal links, and comments on other's pages helps significantly.
Some bloggers have monetized their blogs that include pay per click ads, banners, test links, business referrals, Google AdSense and pay per posts. Some blogs with a high public rating can make substantial amount of money per blog. However, most blogs don't engage in this type of marketing.
The key factors to remember when looking for blogs to advertise are public rating, nature of the content and visitors. The public rating represents the amount of links to the sites, the content relates to the topics on the blog (you don't want to sell business software on an pet site), and the amount of visitors (the more visitors the more that come to your site). You should consider the quality of the writing and the integrity of the writer. You don't want to put your information on a site that may damage your good name.
