The data science Venn diagram
Drew Conway posted this on his blog in 2010, after a meeting where nobody could agree on what a data science course should teach. His three circles were hacking skills, maths and statistics knowledge, and substantive expertise, with data science in the middle. It has been redrawn in talks ever since.
Hacking plus maths is machine learning. Maths plus expertise is traditional research. Hacking plus expertise, with no maths, is the danger zone, his name for someone who can get an answer out of data without knowing whether it is right.