Apple's new Force Touch Trackpad comes with Force Click.
Force Click is a convenient way to invoke secondary actions with what is, in essence, a secondary, "deeper" press into the trackpad. Apple currently ties Force Click into the Quick Look, Look Up, data detector, and detail view functions, as well as a few extras. That means you can generally go deeper just by — wait for it — going deeper. Here are all the basics!
Note: Force Click is currently available on the 2015 MacBook and 2015 MacBooks Pro, and the new Magic Trackpad 2.
1. See all app windows
Force Click on an icon in the Dock and you'll get an Exposé preview of that app's open windows.
4. Look up a word
Force Click on a word or common grouping of words and a you'll get the Look Up popover with results from Dictionary or Wikipedia.
5. Preview a website
Force Click on a link and you'll get a popover showing you the contents of a link's webpage.
6. See Message details
Force Click on a thread in Messages and you'll call up the details view with location, attachments, and Do Not Disturb.
7. See Reminders details
Force Click on a reminder to see location, time, and other details about it.
8. See event details
Force Click on a Calendar event to see location, time, and other details. Force Click on an attendee to see contact details.
9. Add an event
Force Click on a date and you'll get a popover offering to add them to your calendar.
10. Preview an address
Force Click on an a address and you'll get a popover showing you a map of the location.
12. Track a package
Force Click on a tracking number and you'll get a popup showing you all the shipping and delivery details, including progress and current status.
13. Annotate an image or PDF
Force Click on an image or or PDF in Mail and you'll open it in the Markup extension, ready for annotation.
14. More shortcuts
Apple is also using the pressure sensitive aspects of Force Click to let you accelerate fast forward and rewind in QuickTime and iMovie, and zoom in maps. The company is using the Taptic engine to hint when you're getting to the end of a clip in iMovie and to rotating back to zero degrees in Photos. It's safe to say we're at the very beginning of Force Click, and that there's a lot more to come!