Infographics

As Wikipedia explains, “Information graphics are visual devices intended to communicate complex information quickly and clearly”:
Information graphics or infographics are visual representations of information, data or knowledge. These graphics are used where complex information needs to be explained quickly and clearly, such as in signs, maps, journalism, technical writing, and education. ... They illustrate information that would be unwieldy in text form, and act as a visual shorthand for everyday concepts...

Free Online Tools For Creating Infographics
Stat Planet
Stat Planet allows you to create some amazing interactive visualisations, which you can then use as is or create a static image. It can be used within your browser or downloaded for free. Stat Planet gives you access to some great world data and lets you customise that in your visualisations. It also has some great map-based visualisations to try.
Hohli
Hohli is an intuitive, simple online chart maker. It’s incredibly easy to pick your chart type, add some data, vary the sizes and colours and see the finished chart. The finished charts are also very well designed and look great!
Creately
Creately lets you make easy-to-make diagrams and flow charts (easy to collaborate too). When you start, you can choose from a number of purpose-designed diagram types and quickly add your data to make your own chart. The end result looks very professional.
New York Times
New York Times’ Visualization Lab lets you use statistics from recent NYTimes articles to create visualisations in various formats. You can also see other people’s visualisations and see how other people choose to display the same data.
Many Eyes
Many Eyes lets you upload your own data or use data already stored on the site. The visualisations themselves are well-designed and very professional-looking. This is definitely the easiest way to use your own data for online visualisations.
Google Public Data
Google Public Data lets you easily take public data and transform it into an infographic of your choice. These beautiful, colourful graphics simplify and communicate the data perfectly.
Wordle
Wordle lets you create word visualisations using text you enter. There are plenty of interesting designs to choose from. Enter whole books, short passages or see what other people have used. In this example, we can see the US constitution visualised.