I think that Alan Smith and David McCandless both had significant impacts on how I view data visualization.  In Smith’s TEDx talk he shows how numeracy skills are surprisingly lacking, how bad we are at perceiving statistics about society, and about how he used strategies to represent numbers through icons rather than presenting fractions and percentages.  McCandless’s TED talk shows how relatively simple charts, with context of other data, can uncover interesting insights.  I think that both of these talks hint that visualization creation should take the audience into consideration.  Smith wanted to create an engaging tool to show us how our perceptions about our areas compare to actual facts about it, but was aware of how bad many people are at basic math skills and adjusted accordingly.  McCandless talks about how bad we are at putting big numbers in context and adjusts his examples by making comparisons and normalizing data.  As always, context is key.  This is true for both extracting meaning data as well as determining the skills and literacy of your prospective readers.