A personal hotspot is a feature on the Apple iPhone that shares its cellular Internet connection with another device via USB, Wi-Fi or Bluetooth. Connecting a computer via Personal Hotspot allows it to get online anywhere the phone has service.
Tethering an iPhone provides a convenient Internet connection at a moment's notice but comes with several limitations. Personal hotspot connections are not as fast as a standard land-based Internet connections. The phone requires good reception, and electromagnetic interference and excessive distance from cell towers can increase its latency and decrease its throughput. Many service providers set limits on data usage, and exceeding them can result in overage charges. Tethering quickly drains a phone's battery, especially over Bluetooth and Wi-Fi.