Sometimes it's more then interesting (and fun too) to go back in time and check what kind of predictions people made. I found one of those market predictions from 2002. You may think the data is out-dated - but it is still worth reading.
This article gives you a great overview of all the different trends and conditions that will drive the Wearable Computing market the next years.

The prediction was: "...will grow by more than 50 percent each year through 2006. Shipments Totaled more than $70 million in 2001 and are expected to reach $563 million in 2006" and "The true potential for wearable computing in 2006 could be well over $1.3 billion."

That's kind of optimistic, however, depending how you count the numbers this could be true next year.

Some of the proper comments:

"A key application will be bio-monitoring, which collects information for medical purposes, the report said. Taking this a step further, some parents are already fitting their children with wearable monitors that can be used to track their whereabouts."

The report was based on a Web survey and individual interviews with 471 consumers, as well as industry executives.