First, UX theory includes a couple of horizontal word patterns. So, us two lines of text. Given, proper netiquette to limit micro-blog posts to two lines.
Two Lines Netiquette Micro Blogs
Brevity is a hallmark of great writing. Internet users are known to enjoy short works. It follows, micro-blog readers like great work. Given, we read and follow those who write brief blogs.
Writing is a visual cue that a blog post is brief. Also, a micro blog post is a status update. However, there are networks dedicated to this short form opinion.
So, social media posts can be small. For certain types it is preferred. And so, status updates are included.
Micro Blogs Character Limits
Followers do not read posts that are longer. One reason is that they are often delivered in a two line format that truncates additional characters.
When users cannot see an entire post they do not read it. It may be too long.
Micro Blog Limits Netiquette
It is proper netiquette to limit micro-blog posts to two lines because that is all followers will read.