This project is a great example of data logging directly to a cloud web service. You can extend this project in a lot of interesting ways, such as:

• Add more thermistor probes or different types of sensors to log more data. To do this look at modifying the payload sent to DynamoDB so it has more columns of sensor data.
  
• Create multiple instances of the hardware, all logging to the same table. DynamoDB is quite scalable and should be able to support hundreds or even thousands of sensors writing data.
  
• Use the signature generation code in this sketch to call other Amazon web services. For example Amazon has services for storing file data (S3), asyncronous communication (SQS), notifications (SNS), and more.
  

Have fun with the project!