Optimal Article Length
Introduction
For SEO purposes, 
an article should be neither too long nor too short. Optimal article length is between 250-500 words long with keywords appearing throughout the text.
What Determines Optimal Article Length
Web pages aren’t read the way books and periodicals are. The average Internet user isn’t looking for a book to read. He or she is searching for specific information. Because of that, he or she jumps over articles quickly, looking for keywords. If the text is long, it takes too long to scan and seems unreadable. He or she will then leave the page and search in another page.
An article of about 250-500 words is good optimal article length. Articles longer than 600 words stand almost no chance of being read in full. Online readers have very short attention spans, so keep your articles short and to the point.
Optimal Article Length and Keyword Density
There is a lot of talk about the number of keywords to put in each optimal length article. This isn’t such a big deal as you may think. Just make sure your articles flow naturally. Sometimes you can get away with repeating a keyword often, other times you can’t. Write it in a natural way. When you’re done review it and add/remove keywords as you see fit. An article of 400 words with 3-6 instances of your chosen keyword is fine.
Optimal Article Length and Article Structure
Besides sizing your article correctly, you want to structure it well too. Every good article should have an engaging first paragraph. It must answer the reader’s question directly, or encourage him or her to read further on.
The article must have clear section headings. Online readers skip over articles almost always. You want to help them find what they need. Each heading must be followed by a paragraph or two that clearly explains the heading.
A closing paragraph can be a good thing for two reasons. First, some search engines place importance on keywords that appear in the last paragraph. Second, it tells the reader what to do next. Your readers will probably jump from the start to the very end, so this is important if you want them to do something.
Optimal Article Length and Multiple Pages
You can divide a long article into several pages. This can be good or bad. Some readers don’t like having to turn the page and wait for each page to load, especially if it’s slow. But breaking up your article into multiple pages may help with your search engine rankings and also your clickthroughs if you use AdSense. More pages means more exposure. It can also make a long article (more than 600 words) more readable.
