As you may or not be aware, some search engines search for exclusive, specific or rare content. They look for content on your site that is not available from other sources and once they find it they then rate your pages accordingly. The beautiful thing about blogging is that your content does not have to be long or elaborate in order to get across a unique, point or piece of information that will impress the search engine. In fact the basic structure of your log should consist of about two hundred and fifty words of commentary and server who link or two to some interesting sites (including something on your own!)
There are individuals who write longer blogs but instead go to other sources on the web and rewrite articles that they have found. The problem with this tact is that a search engine spider may be able to note if it has seen this type of information before and not rank your blog page very high.
It is also a good idea to lure the search engine spiders by adding material frequently to a blog. When you continually refresh material it keeps them coming back. For instance if you have a 1200 word article on search engine optimization you would like to post on a blog you are better off to divide that article into 400 word pieces and have each of them discussing a different virus. Dividing longer articles into shorter pieces is a way of making the most of its marketing potential.
It also helps if you think of your blog as having a specific goal or purpose that it must achieve. This is what will possibly make your exclusive content different then any other type of information that the search engine spiders and robots may have run across while searching for material to index. The more focused your goals are the more unique your blog content is likely to be.