We recently wrote about the growth of wireless-only households in the US. Quite serendipitously the US Center for Disease Control just released its latest findings on the state of landlines and wireless households in the US:
The official "wireless only" number according to the US CDC is 17.5%.
The most important market segment (from our point of view) is smartphones since they drive data plan and mobile Internet adoption. However SMS-based mobile marketing campaigns wouldn't be impacted by a decline in handset sales because all handsets are text-enabled.