unintended consequences

The author of "Lumines", the hit PSP game, came out with this tidbit while talking about his gadgets:

About five or six years ago in Japan, all of a sudden, chewing gum lost its popularity. The gum manufactures were wondering why, so they began taking surveys. One cause that they found was that cell phones were taking the place of chewing gum by monopolizing people's mouths. So when people are bored at the station or wherever, they gradually have been using cell phones more and more and thus have cut back on their idle gum chewing.

(He goes on to say that the market's recovered somewhat, thanks to cavity-fighting gum. Whew!)