The best way to write on the web is to use the journalistic style. Also called the reverse-pyramid style, this kind of writing puts the most important aspects of the story at the beginning and gradually works its way to the least-important details. In the same way that a good journalist knows that he/she must grab his/her reader from the beginning, so does a good web writer know that most readers just scan headlines, the first sentence, and maybe the first paragraph.
There are two main reasons this happens online.
First, there is the physical situation: the monitor resolution, backlights, fixed reading distance, etc. All of these contribute to a shorter attention span for the reader.
Second, the online reader has readily available a bunch of other websites to click to if he/she does not find what he/she is looking for immediately. No matter if your website is the definitive source of knowledge of a particular subject, if it does not give the reader instant gratification, he/she will go to the next source that does, even if the information is not as good.
Information. This brings up another key point: while people reading a newspaper are reading it to see if it has any useful information, people reading online are most of the time searching for specific types of information. When researching for this piece for example, I was not randomly searching the Internet for anything. I specifically typed into the Google search, “Why is writing for the Web different?”
Even when looking for something that specific, searches will turn up a ton of options to choose from. The best way to sift through those options is to only read the headline, first couple of sentences, and/or an introductory blurb if it exists. If you do not find what you are looking for, you hit the back button and go to the next option.
All of these issues make it necessary for web writing to be concise, easily readable (scannable), and SEO optimized.
A lot of the ideas of the above piece are a summation from the article, “Why Web Writing is Different,” by Tiffany Sanders (http://www.gnc-web-creations.com/web-writing.htm).
Writing Long for the Web
There is also text on the Web that breaks the mold of Web writing, able to last for pages and still keep readers engaged. Most of this content has one thing in common: a fan base.
Popular Science, for example, has had a loyal list of followers for many years. Some followers are specifically fans of authors and editors of the publication. Because of this, and because it operates under the moniker of a magazine, the Popular Science website can get away with articles of magazine-story length.
The other kind of content with a fan base that supports longer stories is niche content. This could be anything from a normal article to a wiki. But a lot of niche audiences are so engrossed in what they are fans of, they want to consume as much information as possible about it. That is why, for example, there is an entire wiki devoted to the videogame, “World of Warcraft.”
What keeps people reading these long articles? Tiffany Sanders says it best: “know your audience.” Are they professionals in a scientific industry, which allows you to write in highly technical terms? Or are they casual science fans who need to be re-taught scientific principles within certain articles? Are they a mixture of both? When you find your audience, you can figure out what their interests are, and thus figure out how to keep their attention.