A successful Web site has the information that users are seeking and is presented in a way that makes sense to them. Thoughtful selection, logical organization, and clear and visual writing are critical components of a usable Web site.
Reading online is different than reading print materials. Typically web users scanthe site looking for relevant words that match the information they are seeking.
Most users scan the page, picking out keywords and sentences. Nielsen (2008) found that 79% of users scanned Web pages; they read only 20-28% of the words on the page.
Since we know that the majority of users scan the page content, we should write in a style that accommodates that behavior. Large masses of text are overwhelming for users with short attention spans.
You will want to use a technique called chunking. Chunking is nothing more than breaking your text into manageable sections. These techniques will help you to chunk your information and write visually:
Clear writing is simple and direct and makes you want to read more. It uses short sentences and words that are easy to understand. Use these techniques to write more clearly:
We recommend using AP style to maintain consistency in spelling and punctuation.
From Purdue OWL (View more at source)