Infographics are a way to deliver data visualisation to an audience. They’re not just about data visualisation though; the data is presented within a story to communicate a specific message.
They can spread like wildfire online and there are a few reasons for this. First of all, visual data is more memorable and has more impact than straight-up facts. If done right, visual data is easier to understand than simple tables (I say in certain cases because when done wrong data visualisation can mislead and confuse, but I will get to that later on).
The second reason for the widespread use of infographics on the web is the fact that they can add a lot of value to a web site and make visitors want to actually check out its content, while encouraging interaction.