If we perceive research as a process of communication. Translating the actual research into an information extraction or retrieval process which finds its end by synthesizing and concentrating those new bits of information into insights and knowledge. Knowledge that needs to be communicated to other scientists, decision or policy makers and the public, so that it can result in a call or need for action.
It sounds simple but it has a fundamental problem: the communication between those groups is difficult due to differences in their knowledge foundation, which creates a communication barrier within the communication process. Visualization is one tool to overcome this barrier and help communicate scientific insights to a broad audience.
Visualization itself is nothing new. Early popular examples can be found in the early/mid 19th century, for example the mapping of cholera infections in central London by John Snow in 1854, the mapping of Napoleons march towards Moscow by Minard in 1869 or the visualization of causes of mortality by Florence Nightingale in 1856. John Snows map is a good example for expert tools, which help scientists better understand their data by taking a new perspective on a problem. By mapping the Cholera infections on a map, John Snow was able to identify a well as the possible source for the outbreak. After sealing the well they were able to contain the contagion. And the example by Florence Nightingale illustrates the power of visualization as a tool to communicate complex data to non experts. Mrs. Nightingale was trying to improve hygiene in british military hospitals during the crimean war. She had a hard time convincing policy makers through spreadsheets and reports, so she created visualizations as a tool to communicate her insights.
The most important change from my point of view since then is the democratization of available tools and technologies. There are many applications available for free and some of them even under open source licenses:
General Visualization Tools
Many Eyes by IBM
Google Refine / Google Charts / Google Fusion Tables
R (powerful open source alternative to SPSS, ect.)
ColorBrewer (Research on color sets)
Gephi (Network Visualization)
The three tools mentioned above are only a small subset of the available tools. The people at Interactive Things have created a great repository of tools available: