Great question! You can see what a viewer clicked on by scrolling down on your Dashboard to the 'Recent Marketing Materials' section and clicking on the title of your marketing piece.
You can also click on the title of any completed marketing piece from your 'Marketing Materials' page. This will bring you to a page that includes all of the stats for that marketing piece.
If you scroll all the way to the bottom, you can see which links have been clicked, how many times, and by who.