Blog post at HowToWriteBetter.net : It's a well known fact that people reading text - particularly online - tend to skim or scan it rather than read it word for word. By skimmi[..]
Blog posts are very different from newspaper articles or even university papers. They cater to a large audience who may not have the time or be interested in reading long blocks of text.
As a blogger, it's important to remember that visitors scan and skim content.
Suzan St Maur lays down the basic in an easy-to-understand article.