Catherine pointed me at some really interesting research that she has been doing recently, highlighting the impact of various forecasts for future supply/demand of embedded devices.

Forecasts from the EU’s Artemis initiative predict “more than 16 billion embedded devices by 2010 and over 40 billion by 2020”. [source] 

The World Wireless Research Forum’s (WWRF) prediction is even more optimistic – “7 trillion devices for 7 billion people by 2017” – in other words, around a thousand devices for every man, woman and child on the planet. [source]

The market for mobile phones and PCs seems to be ultimately bounded by the number of potential users (e.g. population). This is not the case for embedded devices; with so many opportunities for devices as ubiquitous and “invisible” computing elements, the user/device relationship is often nonexistent.