I found this to be an interesting phenomenon, advetisers are looking to target people based on this internet access outside of home and outside of work. Research shared says that many people are OOH (and office) up to 5 hours per day, but are still connected.
Here are some stats:
“Since June 2004 through June 2009, there has been 400% growth in public Wi-Fi hotspots worldwide. New York ranks No. 1 with 887 access locations for the top U.S. cities, followed by San Francisco at No. 2 with 872 and Chicago at No. 3 with 792.
In North America, public Wi-Fi access users jumped to 18.4%, up from 5.4% in March 2009. The majority — 55.3% — of people access public Wi-Fi through hotels and resorts, followed by 27% at airports, 10.5% at coffeehouses, 4.4% on cruise ships, and 2.7% on metro”
From what the article says, this would be a replacement for billboards. This is an interesting way to accomplish the same goal- with a ton more targeting potential.