Steven Musil of CNET writes:
"iPhone and iPod users may experience a "small and quick" shock via their earbuds due to a buildup of static electricity, Apple warned Monday.
People listening to one of the devices in extremely dry air are most at risk of receiving a static electricity shock through the ear buds, according to a warning posted on Apple's Web site. The post likened the condition to the discharge that occurs when a person drags his or her feet across a carpet then gets a shock by touching a door knob.
However, Apple asserted that this condition did not necessarily indicate that Apple's equipment was malfunctioning."