Your content is one of the things that make you rank higher in Google especially after all the changes Google has made in the last few years.
Now days the content of your posts is more important than ever and you really invest your time in writing good content and not that publishing short 4 sentences post.
WordPress has a very neat feature and under every post you write you can see the the number of WordPress very easily.
But watching the words count every time you write a post can be very annoying.
Using a simple code that can added to your functions.php inside your theme, you can set the minimum number of WordPress every post must have.
Add this code to your functions.php or even create a new plugin for it and you will not be able to save the post unless you have written 500 words.
$content = $post->post_content;
if (str_word_count($content) < 500 )
wp_die( __('The current post is below 500 words, please add more information before you save the most again.') );
We are going to release similar free plugin with more friendly notification and more features for this task on the WordPress plugins directory soon.