At the beginning of this year, WiMAX provider Towerstream announced it was getting into the Wi-Fi hotzone game with the aim of becoming a wholesale provider to operators desiring to offload heavy mobile data traffic. Today, Towerstream's Manhattan market is nearly complete with 1,000 access points. Moreover, Towerstream typically sees more than 100,000 unique devices on its network per day, and each hotspot is backhauled by a 400 Mbps radio, which can be programmed to jump to 800 Mbps, allowing Towerstream to offer nearly endless capacity. But Towerstream has yet to sign an offload deal with an operator. The company's case highlights a continuing issue for carriers: Do they build their own Wi-Fi-offload networks or partner with others? Special feature