As an exercise physiologist and R&D consultant for GenoMyx, I can tell you my focus is on the latter "identifying known compounds and theorizing and researching new uses for them".
Most of my consulting research is secondary - i.e.: Compiling the results of other researchers experiments (primary research) in order to form a hypothesis. Analyzing the collective effects of a compound in different populations across varying methodologies allows me to make suggestions regarding if the supplement may be beneficial, and if so to whom under what conditions - a wider scope.
As a doctoral candidate, I perform primary research with a narrow scope. I compile the results of previous work, develop questions that have not been answered, design and carry out experiments to answer these questions. For example, betaine has been shown by some to improve strength and power in recreationally trained athlete. In animals, betaine significantly improves body composition. I have a several hypothesis of how it works physiologically, but I what I want to know is: can it improve body composition and strength in resistance trained athletes? And thats what I'm testing this winter and next spring.