Do you know that infographics are getting more and more popular nowadays until some people use it to gain visitors from Digg and Google!
This is how the system works:
First, they created an attention-grabbing infographic that people want to share. After that, they submit their infographic to Digg, and get their network of Diggers to push it to the front page.
Finally, they included new code beneath their infographic with high value keywords such as “online schools” so that it will be easy for people to link to the infographic.
As more and more people link to that infographic, the PageRank will be improved, your site will be shown on the first search page result for any high value keywords. You need to beware of that!
The following infographic via buzzfeed will give you more detailed explanations.