Aside from a high resolution “Retina” display and a new, thinner profile, Apple’s new MacBook has one feature you need to know about—whether your next computer is a Mac or not. The new MacBook is the first Mac to have a USB Type-C port, and one of the first computers with this new technology. But expect to see lots of new PCs and Macs with USB Type-C ports over the next few years.

If you’ve bought a laptop within the last 15 years or so, it almost certainly has a couple of USB ports. The small, rectangular port connects keyboards,...