Improper use of text alignment is one of the most common and overlooked mistakes of web design. Yet the impact that it has on online readability simply cannot be overlooked. Surprisingly, very few people talk about it or understand its significance.
From the birth of the Internet, people have been taking the rules of text alignment for print and applying them to the screen. But onscreen reading is up to 25% slower and causes more eye strain than reading something in print. Therefore, the text alignment guidelines that work beautifully for print almost always cause readability issues when used online.