Here are a few applications. Reactions are speeded up, tiny quantities of reactants are used, less energy is needed and novel processes become possible.
George Whitesides Lecture Ted Talk
Microfluidic Droplet Generators —Micronit
New Tools for Molecule Makers (PDF Download)—University of Cambridge (Ley / Baxendale)
High Throughput Screening —University of Cambridge (Huck / Abell)
Fundamentals and Applications of Microfluidics— Nam Trung Nguyen,
Steven T Wereley : Northeastern University
Microfluidic Publications of the Quake Group Stanford
Review of Continuous Flow microfluidic PCR in droplets: Advantages, Challenges and the Future Yonghao Zhang Hui-Rong Jiang
Aventures Microfluidiques #1,#2,#3 – In French!
Programmable Microfluidics (Video lecture) —Stanford
Microfluidics Application Areas – Wikipedia
A Controllable and Integrated Pump-enabled Microfluidic Chip and Its Application in Droplets Generating – Nature