Feeds are the core of the Adafruit IO system. The feed holds metadata about the data you push to Adafruit IO. This includes settings for whether the data is public or private, what license the stored sensor data falls under, and a general description of the data. The feed also contains the sensor data values that get pushed to Adafruit IO from your device.
You will need to create one feed for each unique source of data you send to the system. For example, if you have a project with one temperature sensor and two humidity sensors, you would need to create three feeds. One feed for the temperature sensor, and one feed for each humidity sensor.