Anyone reading more than a few blogs realizes there are common characteristics among them. Many could argue blogs are analogous and it is easy to echo that opinion. There are valid reasons why blogs generally look similar and even identical.
One of the main reasons is that blogs are maintained and published by a certain group of blog publishing systems and bloggers frequently use the same suit of templates they try to tweak to make different from other blogs. The reason why bloggers use the same blog publishing systems and templates is probably that by using these systems and templates almost anyone with minimal computer skills can start a blog and start publishing their opinions, recommend interesting links and contribute to the community that the Web is today.
To end this root cause analysis, it is clear the main ingredient of any blog is the written word, the content of the blog, and the similarity and common characteristics of blogs in general makes them very easy for users to read, navigate and engage in conversations often triggered by a single blog post.
After exploring hundreds of business blogs the most common layout and design is a page wide top containing one or more of decoration, title and menu bar and below is a three-column container with navigation links, text or image advertisements and resource links on either side and the actual content, the text, in the middle.

There are variations of this design, but this is the one most frequently used. There is a high probability that the location of advertisements, text ads or banners, is in a column to the right of text content, which makes sense since it is a known Web page hotspot.