LPWA networks are attracting extensive attention because of their ability to offer low-cost and massive connectivity to IoT devices distributed over wide geographical areas. This article provides a brief overview of the existing LPWA technologies and useful insights to aid the large-scale deployment of LPWA networks. In particular, we first review the currently competing candidates of LPWA networks, such as NB-IoT and LoRa, in terms of technical fundamentals and large-scale deployment potential. Then we present two implementation examples of LPWA networks. By analyzing the field-test results, we identify several challenges that prevent LPWA technologies from moving from theory to wide-spread practice.