Where did this fitness trend originate from and why is it so big?

While Nike and Fitbit have been targeting the niche of fitness tracking technology for sometime, Samsung's announcement today - in association with a swirling of Apple rumours - have got me wondering why this trend is gathering steam? The only reasonable deduction I can come to is the success of Wii Fit, which, according to Wikipedia, is the third best selling console game in history with 22.67 million copies sold as of March 2012. This leads me to believe that other companies have cottoned on to this success and are attempting to apply it to other popular consumer technology markets. In fact, Nintendo themselves even hinted at moving further into the health and fitness market in their last earnings call.

What is more interesting, is whether this trend will prove to be successful. It seems that the smart watch market is still in its infancy, struggling to find an identity (which many argue Apple will create, and set the standard for). However, it seems that the only instance in which the average consumer is willing to put something on their wrist apart from their watch and jewellery is to monitor their health. This perfectly explains Samsung recent Galaxy Fit, but once again, it's far too soon to comment. The Pebble is of course an exception to this trend, but, it seems as though it's targeted more towards the power users.

Does fitness tracking interest you?
Will fitness tracking result in the success of the smart watch, or will it merely be an added feature?
Do you think this concept has longevity?