The Sat-Fi is a satellite antenna that's connected by a cable to a Wi-Fi router. It has apps for iOS, Android, Mac OS, and Windows, and lets you make voice calls, send emails, or even update your Twitter and Facebook accounts when you're in places with no network connectivity.
Many mirrorless cameras are designed to be smaller, easy-to-use, somewhat less-capable alternatives to DSLRs. But the Fujifilm X-T1 has a different goal in mind. It's built to replace a DSLR camera entirely.