Remember when Wayport, before ATT bought them , wanted to work with ISP's? I had a few people interested but for the most part, no one really cared. This was almost 2 years ago. Now ATT owns Wayport and over 20,000 hotspots, that it's customers get to use. Wi-Fi is the 5th wheel - phone, broadband, TV, cell, wi-fi (mobile internet access).
CableVision built up a wi-fi network on Long Island for its customers. (It competes with VZ and FiOS there). Qwest is now offering ATT wi-fi to its broadband customers, which besides price gives them one more reason for customers to stick with the Incumbent over, say, the independent ISP like you. Verizon is looking at Boingo.
What's driving it? Laptop, netbook and iPhone penetration. Layoffs, mobile workforce and entrepreneurs. Our stay connected society. I mean, we even have wi-fi on planes - the one place that I could disconnect. Not any more.