As someone notes in the comments: "As they say, a picture is worth a thousand words. Somehow seeing things with a picture adds a whole new dimension."
Infographics can be a great way to quickly reference information.
Instead of pouring over figures and long reports to decipher data, an infographic can immediately make apparent exactly what a dataset actually means...
Some are incredibly practical, some provide information that might be of interest to designers and some just present data that might be interesting to those who design websites all day.