Wow, incompatibility is going to be rampant.
The Google "smartwatch" will connect with Google Shoes, the xphone, the Google TV, possibly the new Xbox and Google Glass.
The Apple iWatch (as some current rumors suggest) will connect with the iPhone, the iPod touch, the iPad, etc. The rumored iRing will connect with the iTV.
The Samsung Smart Watch will connect with Samsung smart phones through Android.
Three watches and all 3 connect with something different. Why.