Project Ara's modules will be hot-swappable
You might find yourself in the middle of taking a picture when you realize that a better camera is needed for this job. So out snaps the camera module on your phone and in snaps the new one. No need to shut down the phone. No fuss, no muss.
During his speech, Eremenko also revealed that modules will be available from an online store, similar to the Google Play Store. The first Project Ara phone will be powered by a modified version of Android L. It's all shaping up to be a fascinating idea, although at this point most smartphone users are probably happy just to keep the status quo for now, anyway.
source: Linaro, PHONEBLOKS via Engadget