Hotspots are shapes that can be added to a slide and respond similar to a button. Hotspots do not have states and they are invisible. When the learner clicks or hovers over a hotspot, something is triggered; often this will be some kind of information pop up contained in a slide layer or on another slide.
Hotspots are useful when you have an image on the slide that contains irregular shapes. Hotspots can be made to be any shape that can be overlaid on top of other slide objects.
In the following example, there is diagram that was imported into Storyline as a single, large image. Within the image are various irregular shapes and those shapes are made interactive by inserting hotspots on top of the background diagram.