Gadgets are like mini-applications that live on a dashboard in JIRA. They are similar to widgets in most of the smart phones we have today or portlets in most portal applications. Each gadget has its own unique interface and behavior. For example, the Pie Chart gadget displays data in a pie chart, while the Assigned to Me gadget lists all the unresolved issues that are assigned to the current user in a table.
To discuss the in-depth details of gadgets and their underlying technology (OpenSocial) is beyond the scope of this book, but there is much information on this topic available on the Internet, if you are interested in creating your own gadgets to use with JIRA. A good place to start will be the Atlassian documentation at https://developer.atlassian.com/x/IgA3.
