For the past few weeks, commuters on some Tokyo subway lines have been seeing a steady stream of interactive smartphone ads, thanks to a new product called Strappy. Created by Shunkosha, a Japanese printing company, Strappy is a rectangular plastic covering that attaches to the straps hanging from subway car ceilings. Within this covering is a reader that supports the FeliCA NFC standard — the same contactless system behind Pasmo, Tokyo's rechargeable subway cards. Users who place their smartphones over the blue boxes will have their browsers directed to a URL with ads, coupons, or other marketing materials.

Of course, the entire system demands a strong underground data connection, but that's not as imposing a hurdle as it may seem, since NTT DoCoMo, Softbank, and KDDI are already building antennas within Tokyo's subway tunnels. Thus far, Strappy has been installed in cars along the Ginza and Marunouchi lines, as part of a trial run that's scheduled to conclude this month.