With the tremendous growth in mobile data traffic triggered by increases in data subscriptions, powerful devices, and richer applications, operators are seeing Wi-Fi as not only a complementary technology to offload cellular data traffic but also as a seamless extension of their mobile networks. The advent of Hotspot 2.0, enhanced Wi-Fi quality of service (QoS) techniques, and transparent authentication mechanisms between mobile and Wi-Fi networks will pave the way for seamless mobility and roaming between these two technologies and provide a better quality of experience to the end user. With web-based applications like Skype, Google Talk, and WhatsApp becoming mainstream media for communication, operators are looking at the combination of licensed band and Wi-Fi technologies to meet capacity demands. This paper discusses the evolution of basic network Wi-Fi -based hotspots to become the trusted partner of mobile operators. We present architectures and required features for data offload and seamless mobility and provide an in-depth techno-economic analysis comparing various deployment alternatives for data offload in a heterogeneous network. © 2013 Alcatel-Lucent.