I suggest that you figure out how I can embed surveys into my emails.
In my work there is a need to facilitate feedback across multiple country offices. Often we will push them to a Google form or another online data entry form. It would be best if they could enter their responses directly in the emails and hit send back to us. The data coming back could be in CSV or XLS or it could be transferred into a data processing/statistical analysis software.
Also, the example I gave above it only one in which this feature would be utilized.