Often on our RSView screens, we might see an interesting event and save the information to CSV format. The ignition trend allows the option of downloading as a png file but not a db file such as csv or xls. The csv option is much more useful for engineering purposes as you have the value as well as the timestamp and can easily correlate this with information captured in other areas of the plant (e.g. electrical disturbance).
This feature request is for the addition of a right click, download as csv option to the easy trend control. (applies to time series plots the most I imagine)