Infographic submission is the most recent and most effective technique used for purpose of Search Engine Optimization through social media. Infographics are basically type of graphical representation depicting some information or integrated with data.
Interesting visual elements used in infographics can help generate more likes, comments, shares and other social signals that can be an important factor in boosting your SEO efforts.
Infographics are a visually compelling communication medium that done well can communicate complex data in a visual format that is potentially viral. They take deep data and present it in a visual shorthand.
Here is some Infographic submission site list.