If you have logged into the developer portal recently you may have notices a slight change in the list of skills that you have. A new icon now appears.
The new icon leads onto a new metrics dashboard. The Amazon blog has described this change recently. Up until now the only way to get any metrics would be to look at your own server logs (or logging that you did within your skill) or of course using the metrics in AWS. The new metrics however gives a much better understanding of how your skill is being used even down to the level of how many unique users interacted with the skill over a given period.
This information is invaluable in helping you better understand how users are utilizing your skill and allows you to improve your skill.